Throughout the entire marine aquarium trade, there probably is no more recognized animal than a clownfish, especially one that is within a host anemone. Even most individuals unfamiliar with the marine aquarium hobby or marine fish instantly recognize clownfish upon first sighting. Oftentimes aquarists are first drawn into this hobby because of the very first time they witnessed a clownfish swimming effortlessly through the deadly tentacles of their hosts. But is this a good choice as a first aquarium fish? Let's dive into the October issue of 'Fish Tales' and find out.

Meet the Family

Clownfish, although often assumed to be a family of their own, are actually damselfishes of the Family Pomacentridae. Within this damselfish family, the subfamily Amphiprioninae contains the 28 species of anemonefishes, also known as the clownfishes. This subfamily is comprised of two genera, four subgenera, and six complexes. Oddly enough, all but one of the anemonefishes are found within the genus Amphiprion. The odd fish out, the Maroon Clownfish, has a genus all to itself (see below). This monotypic genus was created because the Maroon Clownfish, unlike other clownfish, has a bony cheek spine below each eye located just prior to their gill covers.

"Complexes" are used to further segregate clownfish into species that share similar traits. Six complexes are recognized (see below). The Percula complex is comprised of only two species. These species are similar in that each has three white bands oriented vertically on a variable background, usually in shades of orange to black. Adults of the Tomato complex all have a single white bar behind their eye. Further research will be required, but it is possible that all five specimens of the Tomato complex may be a color variation of a single species. It has been noted that hybridizing has occurred in all species. In addition, captive breeding of the species A. frenatus resulted in color forms of A. frenatus, A. melanopus, and A. rubrocinctus (Marliave, 1985). Members of the Skunk complex are noted as rarely moving outside of their host anemone. Fishes from the Clarkii complex, the largest of the six complexes, also have three white bars on their body similar to the Percula complex. However, they are noted to wander up to several meters away from their host anemone on occasion. They also possess a forked tail which enables it to swim faster than other Anemonefishes. Perhaps this is why they are likely to wander more than their cousins. The Saddleback complex only has three species, and all are noted to have brown to black coloration, with some specimens having a small amount of orange. All three also have white bars or stripes, in some instances appearing as a saddle across their back. As noted above, The Maroon complex has a bony cheek spine below each eye just prior to their gill covers.

The Six Complexes of Anemonefish

Percula:	Tomato:	Skunk:	Clarkii:	Saddleback:	Maroon:
A. ocellaris	A. melanopus	A. akallopisos	A. akindynos	A. latezonatus	P. biaculeatus
A. percula	A. ephippium	A. leucokranos	A. allardi	A. polymnus
	A. frenatus	A. nigripes	A. bicinctus	A. sebae
	A. mccullochi	A. perideraion	A. chagosensis
	A. rubrocinctus	A. sandaracinos	A. chrysogaster
		A. thiellei	A. chrysopterus
			A. clarkii
			A. fuscocaudatus
			A. latifasciatus
			A. tricinctus

In the Wild

All Clownfish are found within the warm waters of the Indo-Pacific region except for A. latezonatus which is located in cooler, temperate seas around New South Wales, Queensland, and Lord Howe Island. Distribution is limited in most species, likely due to the short larval stage, but nevertheless some species are found on just about any reef in the Indo-Pacific region. Amphiprion clarkii has the largest distribution of the subfamily, extending beyond the tropical waters of the Indo-Pacific into the temperate seas off the Japan coast. Likewise, it is found in the cooler waters off the coast of Western Australia, and throughout the tropical waters from Melanesia to the Persian Gulf. In addition to A. clarkii, the subfamily extends to reefs found along the eastern coast of Africa to Tuamotu Archipelago, from the Red Sea to Lord Howe Island. Due primarily to their coexistence with sea anemones hosting zooxanthellae which, in turn, require sunlight, clownfish are generally located only in shallow waters.

Most readers are probably well aware of the obligate symbiotic nature of anemonefish with hosting anemones. This symbiotic relationship between the host anemone and anemonefish is termed "mutualism" as both members of the relationship benefit from the other partner. The single most important benefit of anemones towards anemonefish is protection. In the wild, clownfish are always located within a host anemone. A wild clownfish not hosting within a sea anemone is most often quickly consumed by any number of predators. It is the nematocysts of the sea anemone that ward off the attacks of groupers or other predators of anemonefish. Sea anemones gain several benefits from the hosting fish. In some areas, sea anemones will not survive without their host anemonefish. Butterfly fish are quick to dine upon anemones without a symbiotic partner standing guard. In some cases it has been noted that anemones will be consumed in less than 24 hours after removal of anemonefish (Fautin, 1986). In addition to protection, clownfish will achieve several tasks just from normal swimming. They will aerate the water around the tentacles, they will remove waste from the oral disc, and finally they will provide nitrogenous waste (food) to the host anemone. It is considered folklore, by many researchers, that an anemonefish will capture food items from the water column and "feed" the anemone. This has been known to happen within the confines of aquariums, but has not been witnessed by researchers in the wild.

Some readers, at this point, may be curious why the nematocysts of the sea anemone can offer protection to the anemonefish, and yet not harm the anemonefish. Quite frankly, we still do not know, although several hypothesis have been offered. Schlichter's hypothesis of camouflage was the first one offered, and was generally accepted until 1980. Schlichter's decade long study concluded that anemonefish will become coated with the mucus of the anemone by careful acclimation into the host. The result was an anemonefish that was "invisible" to the nematocysts. Opponents to this hypothesis argue that the shred mucus was a result of acclimation, not the explanation of how the mutualism can take place. Then in 1980 Lubbock released his hypothesis of inert mucus, which showed A. clarkii to have predominantly neutral polysaccharides. These neutral polysaccharides differ from that of the acidic mucus found on non-symbiotic fishes. Additionally, they failed to induce a triggered response from nematocysts, unlike the acidic mucus of the aforementioned non-symbiotic fish. All was well with this theory and Lubbock was a hero until he couldn't leave well enough alone. He took his study one step further and discovered that A. clarkii needed a four day acclimation upon leaving Stichodactyla haddoni for Entacmaea quadricolor. Obviously, this four day waiting period would not have been needed if the mucus of the fish was truly inert. Hence was born the hypothesis of thick mucus, which was rather short lived. It was believed that a clownfish inhabiting a host would have a thicker mucus coating which would in turn afford greater protection from the deadly nematocysts. Lubbock, once again, discounted his own hypothesis when he showed that the mucus coating of A. clarkii not in a host anemone was the same as one that was acclimated to a host anemone. Research continued until Lubbock proposed his hypothesis of customized mucus chemistry, which was based on the principle that a clownfish will reduce the amalgamation of substances within its mucus which stimulate nematocyst discharge. In 1984 the hypothesis of thick mucus was revisited when Brooks and Mariscal tried to discount the hypothesis of camouflage. Instead of discounting the work, they assisted in the confusion. They showed a limited, albeit shortened, acclimation period was required even when anemonefish were previously acclimated to fake anemones created with rubber bands and silicone. This required acclimation did not eliminate the hypothesis of camouflage, revived discussion on the hypothesis of thick mucus, and neither discounted nor proved the hypothesis of customized mucus chemistry. Confused yet? More recently, Miyagawa (1989) proposed the hypothesis of innate protection. He demonstrated that planktonic post larvae are stung when forced into contact with a host anemone. However, juveniles 12 to 24 hours older are not stung by the nematocysts. This 12 to 24 hour period directly coincides with the period that juvenile anemonefish institute a union with its preferred host anemone. Finally, Elliot set his sights on this complex interrelation. In 1994 he attempted to solve the mystery surrounding the mucus of the fish and anemone. What he found was that A. clarkii does not produce or have similar mucus to that of its host anemone, but it will collect the anemone mucus within its own once contact has been made to the anemone and thereby carry both the mucus of itself and the host anemone (Elliot, 1994). His 1997 work detailed how A. clarkii was innately protected from host anemones, however, A. ocellaris and A. perideraion are not (Elliot, 1997a). Furthermore, he showed larvae of ten species of clownfish will all be captured and consumed by the host anemones, but shortly after metamorphose this did not occur to certain species (Elliot, 1997b). Despite all of the research performed on this topic, no clear-cut answer has yet been determined. It remains one of life's great mysteries.

Clownfish definitely have their preferences of hosting anemones, though this preference is strangely not adhered to in captivity nearly as strongly as in the wild. Of the nearly 1,000 species of anemones, only ten species from five genera are ever used as symbiotic hosts for clownfish.

The anemonefish and their known natural symbiotic host anemones are detailed below with the anemone at the top of the chart and all natural hosting anemonefish below. It should be noted that A. clarkii is known to naturally host with each known hosting anemone. It should also be noted that in rare circumstances it has been noted that anemonefish may host in large-polyped stony corals such Euphyllia spp. or Goniopora spp. (Michael, Coral Realm).

Stichodactyla mertensii

A. akallopisos	A. fuscocaudatus
A. akindynos	A. latifasciatus
A. allardi	A. leucokranos
A. chrysogaster	A. ocellaris
A. chrysopterus	A. sandaracinos
A. clarkii	A. tricinctus

At about this time I would expect the reader to wonder how and why clownfish choose the anemone that they do. Thankfully, you are not the only person that has ever contemplated this. Arvedlund, et. al. (1999) found that the eggs of the clownfish were imprinted with cues during the development process. The eggs are laid nearby the base of the host anemone of the parents, where the imprinting occurs. Olfactory cues are imprinted according to the mucus released from the oral disc and tentacles of the anemone. These olfactory cues assist the juvenile clownfish in locating the same species of anemone that its parents preferred. Arvedlund's work was an extension of the work performed by Elliot in 1995 where they concluded clownfish species were able to track the scents of hosting anemones from as far away as 8m down current (Elliot, 1995).

All clownfish females are the result of males undergoing a sex change, or protandric hermaphrodites as they are called. In most host anemones a small harem of clownfish are present. Generally, this harem contains a single female, a single male, and several juvenile fish. The female is the most dominant member of the harem, and her constant attention to the harem ensures that the male does not develop into a female. When the female becomes absent from the harem, the male will assume the role of the female. Once a female, the fish cannot revert back to male. Both the male and female inhibit the sex change tendency of the juveniles. This phenomenon is often referred to as "psychophysical castration." When the male undergoes sex change and becomes a female, the juveniles will battle to determine who the most dominant member is. The winner will then grow testicles and become a male. These sex changes will occur in less than one month. In some instances, immigrating fish may disrupt this natural hierarchy. Some species (A. clarkii) have been noted to roam over 500 feet in search of another host anemone. In these cases, males and females may get thrown out of their host anemone by a stronger individual that left their original host anemone. Generally, these migrating specimens were displaced from their previous anemone in similar fashion. Juveniles will also migrate to nearby host anemones in hopes of moving up in the pecking order. In rare situations, juveniles may skip over the step of becoming a male, instead maturing from a juvenile into a female. This may occur if a male and female are not present in the host anemone, or a roaming juvenile is more dominant than the present female and male.

In most species of clownfish sexual dimorphism is present with the female being the larger of the two sexes. This is most pronounced in Premnas biaculeatus where the male is usually 30% of the size of the female. Although noted in Amphiprion clarkii and A. frenatus, sexual dichromatism is considered rare.

In the Home Aquarium

The majority of clownfish can be kept in home aquariums rather successfully, with several accounts of clownfish surviving for over 20 years. As with any marine fish, certain parameters must be met to ensure a happy, healthy fish. Similar to all the other fish I have covered in this column, pristine water parameters are assumed to be in place prior to introduction of the inhabitants. If optimum conditions are not yet present, this is obviously the first area of concern. For the purpose of this column, "optimum" should mirror natural sea water as closely as possible.

Once water parameters are under control the hobbyist needs to choose a clownfish and determine if it will require an aquarium to itself. Some species, like Premnas biaculeatus, are extremely aggressive fish. Juveniles can coexist with other fish, but as they age, their temperament will change as well. Adults of this species generally prefer an aquarium to themselves. Do not be surprised if Premnas biaculeatus decides to kill its tankmates, preferring to create a species aquarium for herself (and her mate). Despite Premnas biaculeatus gaining the reputation as the "meanest" clownfish, all clownfish are aggressive to some degree or another. Remember, they are damselfish after all. All clownfish will aggressively defend their host and a territory surrounding the host. Assuming you choose a clownfish other than P. biaculeatus, there are some fish that need to be avoided in their aquarium. Basically, any large predators, such as groupers or lionfish, need to be avoided. For these fish a clownfish represents an easy meal. Triggerfish or moray eels should also be added to this list. For a complete list, see below. Please note the list is specifically for Amphiprion species, as Premnas biaculeatus usually requires a tank to itself. However, this does not mean P. biaculeatus can be housed with predatory fish. They will likely either become food for the predators, or kill them in self-defense. Lastly, it is very important to note that for all species of clownfish the corallimorpharian commonly referred to as the elephant ear anemone, Amplexidiscus fenestrafer, will consume the clownfish. Do not place this anemone into any aquarium containing clownfish.

Compatibility chart for Amphiprioninae:

Fish	Will Co-Exist	May Co-Exist	Will Not Co-Exist	Notes
Angels, Dwarf	X			Should be excellent tankmates.
Angels, Large		X		Large Angels may become territorial.
Anthias	X			Should be excellent tankmates.
Assessors	X			Should be excellent tankmates.
Basses			X	Adults may consume clownfish.
Batfish	X			Should be excellent tankmates.
Blennies	X			Should be excellent tankmates.
Boxfishes	X			Should be excellent tankmates.
Butterflies	X			Should be excellent tankmates.
Cardinals	X			Should be excellent tankmates.
Catfish			X	Adults may consume clownfish.
Comet	X			Should be excellent tankmates.
Cowfish	X			Should be excellent tankmates.
Damsels		X		Best avoided except for large aquariums.
Dottybacks		X		Some dottybacks are very aggressive and are best housed by themselves.
Dragonets	X			Should be excellent tankmates.
Drums		X		Drums can become aggressive. Clownfish in first.
Eels		X		Some eels become large enough to consume clownfish.
Filefish	X			Should be excellent tankmates.
Frogfish			X	Adults may consume clownfish.
Goatfish	X			Should be excellent tankmates.
Gobies	X			Should be excellent tankmates.
Grammas	X			Should be excellent tankmates.
Groupers			X	Adults may consume clownfish.
Hamlets	X			Should be excellent tankmates.
Hawkfish		X		Large hawkfish may consume clownfish.
Jawfish	X			Should be excellent tankmates.
Lionfish			X	Adults may consume clownfish.
Parrotfish	X			Should be excellent tankmates.
Pineapple Fish	X			Should be excellent tankmates.
Pipefish			X	Pipefish are best housed by themselves.
Puffers		X		Some puffers can become aggressive. Clownfish in first..
Rabbitfish	X			Should be excellent tankmates.
Sand Perches		X		Sand perches can become incredibly aggressive. Clownfish in first.
Scorpionfish			X	Adults may consume clownfish.
Seahorses			X	Seahorses are best housed by themselves.
Snappers			X	Adults may consume clownfish.
Soapfishes			X	Adults may consume clownfish.
Soldierfish			X	Adults may consume clownfish.
Spinecheeks	X			Should be excellent tankmates.
Squirrelfish			X	Adults may consume clownfish.
Surgeonfish	X			Should be excellent tankmates.
Sweetlips			X	Adults may consume clownfish.
Tilefish	X			Should be excellent tankmates.
Toadfish			X	Adults may consume clownfish.
Triggerfish		X		Some triggerfish are incredibly aggressive. Clownfish in first.
Waspfish			X	Adults may consume clownfish.
Wrasses	X			Should be excellent tankmates.

Note: While many of the fish listed are good tank mates for Amphiprion spp., you should research each fish individually before adding it to your aquarium. Some of the fish mentioned are better left in the ocean, or for advanced aquarists.

As with all marine fish, ensuring they receive the proper amounts and type of food is of paramount importance. Clownfish are omnivores, consuming small amounts of red filamentous or blue green algae, though for the most part they consume plankton from the water column. Although the largest portion of their diet is comprised of copepods, food items such as tunicate larvae, echiuroid worms, sipunculid worms, polychaetes, nematodes, barnacle cirri and nauplii, amphipods, isopods, ostracodes among other things (Michael, Coral Realm). In addition to the above mentioned food items, anemonefish will feed upon their hosts. Anemone tentacles have been found in the stomach contents of anemonefish (more on this later). Essentially, their feeding regimen is ideal for marine fish kept in captivity as it makes feeding them a rather easy chore. Any of the meat based prepared foods on the market today should suffice well. Plankton, mysids, and enriched brine shrimp are all good foods to feed in any of the formats they can be found in: freeze dried, live, or flash frozen. Flake or pellet foods geared for the marine carnivore will also be an excellent staple food. Offering a variety of foods is a good idea, so do not become stuck in the rut of feeding the same foods every day. Generally, clownfish will accept any of these foods without hesitation even after recently being added to the aquarium. For finicky fish that refuse to feed, try to obtain live foods. It is rather doubtful that a clownfish can resist live adult brine shrimp or any small mobile planktonic crustacean.

Diseases and parasites in clownfish can be, unfortunately, a common occurrence. This may be their only downfall as an aquarium fish. They seem to be susceptible to almost all marine diseases and parasites. Some of the more common parasites associated with clownfish are Cryptocaryon irritans and Brooklynella hostilis. The former generally can be associated with all species of clownfish, while the latter generally only affects Premnas biaculeatus. The best and possibly easiest method of curing your clownfish from Cryptocaryon irritans, as with all marine diseases and parasites, is utilizing a hospital tank; an aquarium setup for the sole purpose of medicating the inhabitants. In the case of Cryptocaryon irritans a lowered salinity of 1.010 - 1.011 works best. You will need to leave your clownfish in this lowered salinity for a period of no less than seven days. Brooklynella hostilis is another easily-countered parasite. A simple 15 minute freshwater dip generally eliminates this parasite. The final external parasite to be concerned with is known as Amyloodinium ocellatum. Unfortunately, this parasite is considerably destructive and treatment is a crapshoot at best. In most situations, the hobbyist will not realize something is amiss until their fish start dieing. At this point, treatment is probably too late. In the rare situations that this parasite is caught in time, the most effective treatment is copper followed by a day of lowered salinity. The lowered salinity does not kill the parasite, but it will cause it to fall off of its host, thus relieving some of the stress caused by the parasite. Follow up with copper treatment after slowly raising the salinity to a more comfortable level of 1.018 - 1.020. Some clownfishes, especially Premnas biaculeatus, have a difficult time with copper treatments. Therefore, copper treatments should be monitored closely. A copper level of .20 mg/L should be enough to assist in eradicating the parasite, but at the same time will likely not cause harm to your clownfish. The easiest way to eliminate the spread of this parasite is to place your new arrivals into a quarantine tank for at least one month. Severe infestations may require the complete draining of the aquarium and allowing it to become completely dry for several days. It should be noted that captive-bred clownfish are considered to be completely free of this parasite - reason enough to purchase captive-bred animals. As is usually the case, the aforementioned parasites often lead to further complications. The fungal disease commonly referred to as "popeye" is an opportunistic disease usually preying upon weakened fish. If pristine water parameters are maintained and the parasites are eliminated, popeye will often heal by itself with no assistance from the aquarist.

Do clownfish require an anemone in the home aquarium? In a word, no. All clownfish will live out a normal, happy life without ever laying eyes on an anemone in the aquarium. In fact, in the home aquarium some clownfish have been known to smother the anemone to death (Shimek, 2001). This is likely the result of large clownfish essentially loving their smaller host anemone to death. In the home aquarium where water parameters are often less than ideal for host anemones, this seems like it is often the final straw that leads to the untimely death of the anemone. The main reason why clownfish utilize a host anemone is for protection. Hopefully, this protection is not needed in your aquarium. It shouldn't be needed if you designed the aquarium properly with the clownfish in mind. However, for most hobbyists the beauty of clownfish is not complete without them swimming amongst a host. In these situations, any number of animals can be used as a host. Clownfish will host in most any coral when anemones are not present; from leather corals, to zoanthids, and my personal favorite, LPS corals. It should also be noted that clownfish do not necessarily need a coral to host in, either. Clay flowerpots cut in half are often an irresistible host for newly introduced clownfish.

Still can't resist the desire to witness and observe the natural symbiotic relationship of an anemone and an anemonefish in your own aquarium? This seems too great of a temptation for most to resist. If this is the case, first and foremost the hobbyist must become educated on anemones. Anemones do not have a marvelous track record in home aquariums. Most perish in under a year within the confines of the home aquarium. The care of an anemone in the home aquarium is a discussion too great to concern ourselves with in this column, and thus I will not go into the particulars. Previous works on the care of anemones have already been detailed. Therefore, I will simply direct you to a couple of links that have superb information on this topic. Both links are authored by Dr. Ronald L. Shimek. The first link offers detailed descriptions on anemones as a whole, and the second link concerns primarily the host anemones. Please do take a moment to read these columns.

Finally, what discussion on fish would be complete without taking a moment to confer on aquarium size? The size of the aquarium depends upon tankmates for the most part. A pair of clowns by themselves need only a standard 40 gallon "breeder" aquarium (36" x 18" x 18"), though commercial breeding facilities usually use a 20 gallon aquarium. Depending on the size and number of fish you wish to keep with the clownfish, the aquarium size will need to be increased. Also, the amount of the increase will depend on the territory requirements of the additional fish you wish to add. As mentioned earlier, clownfish aggressively defend their territory. An aquarium of limited size containing a hosting pair of clownfish will not afford much swimming space to tankmates.

Captive Breeding

As most hobbyists are probably well aware of already, captive breeding of clownfish can be termed "highly successful." In fact, I encourage those individuals looking into purchasing clownfish to consider nothing but captive-bred fish. They are often a healthier alternative to their wild counterparts. In addition, all (according to Fautin) anemones left without a clownfish defending it, due to collection of the clownfish, will often succumb to the attacks of butterfly fish or hawksbill turtles. This will also result in the death of the numerous other symbionts (crabs, shrimps, and other fishes (such as domino or three-spot damsel fish) living on the same anemone.

For many hobbyists with a pair of clownfish, witnessing your pair breed is a likely occurrence. If you are like the many hobbyists before you, you will in due time try your hand at raising the fry. Although I cannot term this endeavor as being "easy," it can be done.

The whole process will begin with the courtship. Males will begin biting at the substrate and will increase the frequency of this action the closer the mating comes to fruition. This will usually begin three to five days prior to the actual mating ceremony. As the day approaches, the female will join the male in substrate biting. During the final day the pair will become noticeably more aggressive, actively chasing away any fish that come nearby. After a brief courtship, which will include various forms of posturing, the female will lay her eggs upon a flat surface just off the side of their host anemone in the area that was cleared of debris earlier. In species of anemones that set their foot in soft sand substrates, the adult clownfish will hunt for a flat substrate surface to work with. Such items as shells, sand dollars, coconut shells, or most any human litter such as tin cans or plastic have been used. Just prior to sun up the pair will nip at the tentacle of its host causing it to retract in the area where the eggs will be laid. The female will make a few practice attempts at egg laying, then finally as morning begins to take shape, the female will rest her swollen abdomen against the intended nesting site and drag herself, using her pectoral fin, around the site simultaneously releasing the unfertilized, sticky, negatively buoyant eggs. The male swims closely behind the female, fertilizing the eggs as he follows. The actual egg laying will take on average two hours. For a pictorial featuring many of these spawning events, click here.

With the easy part out of the way, the pair must now defend the eggs from potential predators. The female moves away from the nest and usually goes directly into feeding mode, while the male jumps into action and now belligerently defends and diligently tends to the nest. Any approaching predators are quickly attacked by the male who prefers to rely on an excellent offense as his best defense. That is, without hesitation, he will begin attacking and biting the on-comer. When there is no threat present, the male will fan the eggs with his tail to both aerate the eggs as well as removed any debris that may have settled onto the eggs. Though the female will assist the male on occasion, this is not considered to be common practice. In addition to fanning the eggs, the male will remove any unfertilized or fungally-infected eggs by consuming them. Depending on factors ranging from female size to individual species, the eggs will number between 100 and 2,500 eggs. The color of the eggs will take on several different variations as they mature. Generally, eggs are pink to orange in color as they are laid and remain so for a couple days. As the eggs age the pink to orange will gradually fade into a drab grey or brown color. Finally, as the hatching nears, the eggs will become shiny sliver with the developed eyeballs of the fry clearly visible. Depending on which species are involved and the water temperatures present at the nesting site, the eggs will hatch around day seven or shortly thereafter. The eggs hatch as swimming larvae and under the protection of night they join the tumultuous life of plankton. If the larvae win the equivalent of the clownfish lottery and survive, the larvae will settle out in from 8 to 16 days.

Life does not get any easier for larvae in the wild at this point. As the larvae begin to settle out they must find a suitable host anemone before they become food. As is most often the case they do not find a host, but in rare occasions the young clownfish are able to locate a host using their olfactory clues imprinted upon their eggs during development. Once they find the anemone, they will have to make one last fight for life before their odds of survival improve. Somehow, they must fight conspecifics for a spot on the bottom of the totem pole. Again, if they are not allowed to join the hierarchy of clownfish present, it must either continue searching for another suitable host or become dinner. Once the young clownfish prove their worth and are accepted into a host anemone, odds on survival greatly improve.

Luckily for the larvae, life isn't so challenging when spawned in captive conditions. Perhaps these captive-bred clownfish are the true winners of the clownfish lottery, as the odds are considerably better for survival than their wild counterparts. Of course, the final odds depend directly upon you, the caretaker, and your abilities as an aquarist. After successive hatches, you will develop excellent techniques of your own until the odds of survival are stacked in the clownfishes favor.

Day 6 Day 11 Day 14

The reader can clearly see the development of the fry after hatching in this series of photos. At day 6 the fry are already starting to develop. By day 11 the fry already begin to look somewhat orange, and by day 14 they are virtually miniature versions of their adult parents. Photos courtesy of Bob Schulz.

Going into great detail on the rearing of clownfish fry is outside the scope of this column. If done correctly, it would likely require several columns unto itself. With this in mind, I will offer a very basic guide on what is required for successful rearing of fry. Please use this only as a starting point. For a more detailed account, please try and acquire the reference book by Wilkerson (2001), as noted in the reference section below.

Clownfish larvae left in the aquarium with their parents will likely be consumed by the parents. As such, removal of the larvae is essential. The easiest way to go about this is to remove the fry just prior to hatching. Since the eggs are attached to a flattened stone, it may be easiest if you provide this stone for your fish. Shells, ceramic tiles or the bottom of clay pots work excellent in this regard. Once removed, place the stone into its own aquarium. Water movement over the eggs is vital to the well-being of the eggs. A properly placed air stone should suffice nicely. Ensure the air stone is supplying ample water agitation around the eggs.

Prior to the eggs hatching you must make certain that food will be readily available to the larvae. At the time the larvae hatch their overall size will dictate the need to feed them live foods called rotifers. It is likely that the aquarist will need to grow their own live foods unless your local stores are doing this and selling it retail, which is doubtful. For extensive information regarding the culturing of rotifers, check here. Of course, rotifers will require food themselves, so that they are nutritious. Phytoplankton is best used to fill this need and it is rather easily cultured. For extensive information on culturing live phytoplankton, check here. Live phytoplankton can also be purchased from local or online sources, though it may be more economically viable to culture it yourself. You can expect the need to feed live rotifers, and thus culture live rotifers and phytoplankton, to continue for as short as seven days and up to fourteen days, depending on the size of the larvae. This is actually when the larvae metamorphose, and thus are capable of consuming live nauplii. Once again, the home aquarist will have to culture this live food. Explore this week's specials with Lidl Offers! For extensive information on culturing live brine shrimp, check here. By day 15, or possibly sooner, you should make an attempt at transferring the clownfish from live foods to pulverized dry foods with anticipation of feeding exclusively pulverized dry food by day 25 to 30. The food is pulverized so it is small enough to be consumed by the small fish.

In this series of photos the reader can clearly see the development of the fry, from the early stages when they are first laid by the female, to the silver encased eyeballs ready to hatch, and moments after hatching. Photos courtesy of Bob Schulz.

There are three main areas that contribute to the most losses of larvae and juvenile clownfish, and for the most part they can be controlled by the aquarist. Supplying enough food is usually the largest hurdle to overcome. Sometimes, however, the food is available but the larvae and fry are unable to capture it. Water quality can be just as important. Due to the heavy feeding regimen, daily water changes must be performed. If not, the water quality will suffer and you will experience fish losses. Water changes upwards of 50 - 75% daily are recommended. Make-up water should be taken from the show aquarium, and thus freshly mixed salt water replaced into the show aquarium. This will allow for larger water change percentages while still maintaining stable water parameters. The last area that usually claims a large percentage of deaths is obviously the metamorphosis. However, this can be tied together with the two previous causes of demise because the lack of high quality food and sub-par water quality will have a direct influence on how well the larvae are able to cope with metamorphosis. If the hobbyist can avoid these three common mistakes, it is likely that you will have good success.

Meet the Species

Of the 28 described species of clownfish, only about 20 are available for purchase in the hobby with any regularity. Even so, the number is probably closer to ten species that should be considered commonly available. For the purpose of this column, I'll discuss the species within their complexes.

By far the most popular clownfish are those from the Percula complex. Amphiprion ocellaris, or the Ocellaris aka False Percula Clownfish, is nearly identical in almost every aspect to its close cousin, A. percula, or the Percula Clownfish. They are the smallest of clownfish, not quite reaching three inches of total length. Both can be fairly timid as young individuals, but as they grow into an aquarium, they will aggressively defend their limited territory. The amount of territory they claim is among the smallest of all clownfish, likely due to the fact they are very poor swimmers. If a hobbyist wishes to maintain a small harem of clownfish, A. ocellaris is your best option. Members of this complex have been known to spawn in aquariums as small as 10 gallons.

From the Skunk complex come Amphiprion akallopisos, A. perideraion, and A. sandaracinos, amongst others. Like the Percula complex, all of these species are similar to each other in care. They will defend their territory, but rarely settle into an aquarium if aggressive fish are already present. As such, these clownfish should be amongst the first fish into an aquarium. Again, similar to the Percula complex, these fish are hardy aquarium fish. However, they are difficult to get to spawn.

The clownfish from the Tomato complex form another staple of the hobby, and therefore can usually be located in most aquarium stores worldwide. These fish are generally hardy and aggressive, even to conspecifics. Therefore, do not keep more than two specimens in the same aquarium. Adults can reach up to four inches, though males are often roughly half the size of their female companion. The two most commonly available species from this complex are Amphiprion melanopus, the Cinnamon Clownfish, and the namesake of the complex, A. frenatus, also called the Tomato clownfish. Species within this complex are regarded as among the easier species to spawn and raise in captivity. Juveniles will often have up to three vertical white stripes, but eventually two of them fade to leave only a single white stripe just behind the eyes.

Members of the Clarkii complex are fast growers and both male and female can reach four to five inches of total length. Since they do host in all ten of the natural hosting anemones, this complex is more geographically widespread than any of their cousins. Coloration amongst the complex is fairly similar with two vertical white stripes, one just behind the eye and the second stripe occurring in the center of the body. A third area of white is often located at the base of the tail, though oftentimes it never fully develops into a complete white band. Clarkiis are hardy aquarium fish, and spawn regularly with large egg masses, up to 1,500 eggs per spawn. They are the fastest swimming clownfish, most likely due to their forked tail, which is not present on other clownfish. Most likely due to the relative ease of swimming, they are known for wandering farther away from their host than any of the other species. The relative ease to spawn, overall number of eggs, fast growing nature, and willingness to eat anything they can as larvae and fry combines to make members of this complex the best possible candidate for first time clownfish spawners. The most popular of the complex is Amphiprion clarkii, and generally it is available as both a wild captured and captive-bred fish.

The most often mislabeled clownfish, the Sebae, Amphiprion sebae, is a member of the Saddleback complex. In addition, the very first clownfish ever discovered, A. polymnus, is the namesake of the complex as it is commonly referred to as the Saddleback clownfish. This complex is characterized of rare, highly sought after clownfish that have a difficult time adjusting to aquarium life. They are noted as being self-destructive whenever they become frightened. They are a large fish for clowns, maxing out around five inches of total length. Members of this complex are often confused with members of the Clarkii complex. The backward slope of the second white stripe is the most distinguishing feature separating the two complexes.

Right: A perfect example of Amphiprion polymnus, the Saddleback Clownfish. For the aquarist, this is a difficult species to locate as well as maintain. Photo courtesy of Greg Rothschild.
	Left: An unusual and highly sought after dark color variant of Amphiprion polymnus. These are often labeled in the stores as a Black Percula. Photo courtesy of Greg Rothschild.

The final clownfish to discuss is the Maroon, Premnas biaculeatus. Members of this species are noted as being highly territorial. One of the trademark displays of Maroon Clownfish (and other highly territorial clownfish) is the tail-beating of the female as she attempts to procure a suitable nesting area. For detailed photos and descriptions, please take a moment to view this month's edition of ReefSlides. Juveniles can coexist with larger fish and may even be picked on, but as their size increases upwards of five to six inches, the largest of all clownfish, their temperament grows with them. In fact, their temperament is so aggressive that it is difficult to pair up this species. Care must be taken when introducing a male and female Maroon as the female is likely to kill the incoming male. The best way to introduce these beauties to one another is by utilizing fluorescent lighting egg crate to separate the two fish. The male should be able to swim in between the holes, while the female cannot. This affords the male an escape hatch, which will likely be put to use regularly. Males will grow in relation to the female and will average roughly 30 - 40% of the size of females. Two separate color varieties exist, appropriately named the white striped and yellow striped Maroon, respectively. As the name indicates, the difference lies solely in the color of their striping. The yellow striped variety is a classic representation of geographical variety - they are known to hail only from Sumatra. This unique coloration affords them the label of the most sought after Maroons.

Conclusion

The adorable, wiggly fish known as Clownfish are extremely recognizable in, and out of, the marine aquarium hobby. With little effort, a pair of clownfish can be successful kept, and even bred in our reef aquariums. However, these cute fish are not exactly cuddly - they can be very aggressive towards their fellow tankmates. Taking care in the selection of the clownfish and their tankmates will oftentimes yield desired results. Leaping haphazardly into their care will just as often result in failure. Take the extra steps required and purchase a captive-bred animal, which generally results in a healthier fish, and one already accustomed to captive life and foods.

References:

Allen, Gerald R. 1974. The Anemonefishes. Their Classification and Biology, 2nd Ed. TFH Publications, NJ.

Allen, Gerald R. 1979. The Anemonefishes of the World: Species, Care & Breeding; Handbook for Aquarists, Divers and Scientists. Aquarium Systems, Mentor Ohio.

Bloch, M. E. and Schneider, J. G. 1801. M. E. Blochii, Systema Ichthyologiae iconibus cx illustratum. Post obitum auctoris opus inchoatum absolvit, correxit, interpolavit Jo. Gottlob Schneider, Saxo. Berolini. Sumtibus Austoris Impressum et Bibliopolio Sanderiano Commissum. Systema Ichthyol. i-lx + 1-584.

Elliott, J. K., R. N. Mariscal and K. H. Roux. 1994. Do anemonefishes use molecular mimicry to avoid being stung by host anemones? Journal of Experimental Marine Biology and Ecology. 179:99-113.

Elliott, J. K., J. M. Elliott and R. N. Mariscal. 1995. Host selection, location, and association behaviors of anemonefishes in field settlement experiments. Marine Biology (Berlin). 122:377-389.

Elliott, J. K. and R. N. Mariscal. 1996. Ontogenetic and interspecific variation in the protection of anemonefishes from sea anemones. Journal of Experimental Marine Biology and Ecology. 208:57-72.

Elliott, J. K. and R. N. Mariscal. 1997a. Acclimation or innate protection of anemonefishes from sea anemones. Copeia. 122:284-289.

Elliott, J. K. and R. N. Mariscal. 1997b. Ontogenetic and interspecific variation in the protection of anemonefishes from sea anemones. Journal of Experimental Marine Biology and Ecology. 208:57-72.

Fautin, D. G. and Allen, G. R. 1992. Field guide to anemonefishes and their host sea anemones. Western Australian Museum, Perth, 160Pp.

Lieske, E and Myers, E. 1994. Collins Pocket Guide. Coral reef fishes: Indo-Pacific and Caribbean. HarperCollins Publ., London, 400 Pp.

Mariscal, R. N. 1970. The nature of symbiosis between Indo-Pacific anemonefishes and sea anemones. Mar. Biol. 6:58-65.

Marliave, J. B. 1985. Color polymorphism in sibling Amphiprion: is the reef fish lottery rigged. Env. Biol. Fish. 12:63-68.

Shimek, R. L. 2001. Host Sea Anemone Secrets. A Guide to the Successful Husbandry of Indo-Pacific Clownfish Host Sea Anemones. Marc Weiss Companies, Inc. Ft. Lauderdale, Florida. 24 pp. ISBN: 0-9664549-5-2

Wilkerson, Joyce D. 2001. Clownfishes, a guide to their captive care, breeding & natural history. Microcosm. Charlotte, 240 pp.

Online Resources:

Breeders Registry

Coral Realm

Wet Web Media