Gobies are widely considered to be among the most suitable marine aquarium fishes, especially when discussing small marine reef aquaria. However, this is not always the case. In some instances the goby may require large amounts of natural foods that are not always present in the aquarium in endless supply. Other times the natural food is readily available, but the incessant predation upon the micro-fauna of the aquarium creates a less than optimal situation. With this in mind, I'd like to use my September edition of "Fish Tales" to introduce the Sleeper Gobies.

Meet the Family

The Gobiidae is the largest family of marine fish containing over 2,000 species and still growing as new members are discovered regularly. Most Gobiidae are characterized by a few notable attributes. Other than the few gobies that swim above the substrate, most lack a swim bladder and lateral line. However, gobies have sensory ducts around their heads that make up for the loss of the lateral line (Smith and Knopf, 1997). Another interesting characteristic is the ventral fins, which in most gobies have joined as one and developed small suction cups on the end. Also, gobies are demersal spawners with most species having both parents acting as guardians over the eggs (Smith, Knopf, 1997). For this issue I will narrow the field a bit and will concentrate on the genus Valenciennea.

Not unlike most marine fish, extensive confusion with the correct genus name has existed amongst the ranks of researchers. Problems abound right from the start of the first description. Bleeker (1856) originally described the genus, but not before he and others already placed species fitting the description for Valenciennea into the Eleotridae. Often times the correct author is cited, but the wrong reference is cited, most often Bleeker (1868). Bleeker seemed to create this confusion himself as the 1868 work introduced the name Valenciennasia. He referred to it as the same type species as Valenciennea. Some (Hoese and Larson, 1994) believe he did this because the similarity in spelling of Valenciennea to the insect genus Valenciennia. Luckily, some rules have been developed for situations such as this, and when the International Code of Zoological Nomenclature (ICZN) finished with their review, they concluded the 1856 (Bleeker) work was the official first description, and hence we should recognize the spelling as Valenciennea. Still persisting to this day, this genus is incorrectly referred to as Valenciennasia, Eleotris, Calleleotris, or even Coergobius.

Valenciennea is differentiated from its close cousins by having completely separated pelvic fins, a single row of teeth in the upper jaw, and a large fleshy flap located at the gill arch (Hoese and Larson, 1994). Additionally, they are among the largest marine gobies with most reaching over 5 inches and some reaching 7 inches of total length. Fifteen species have thus far fit the criteria to be placed in Valenciennea (see below).

In addition to the fifteen species, several color varieties exist; V. puellaris has at least three noted color variations, while V. sexguttata and V. wardii also have differing color variations (see below).

In addition to the three species with distinctive color variations, there are also slight color variations in additional species. Valenciennea decora exhibits different colors from all three of its known localities (New Caledonia, One Tree Island, and Osprey Reef). Valenciennea alleni differs from northern and western Australia to Eastern Australia. Lastly, V. immaculata from China and the Philippines differs from their Australian counterparts. Variations are all minor, with the most common difference being a slight contrast in background color.

In rare cases, sexual dimorphism has been noted in the caudal fin length of the males of V. parva, V. sexguttata, and V. longipinnis. Likewise, minor sexual dichromatism exists in a few species. Valenciennea parva males are noted as having a black bar above the upper lip, although this has also been seen in a few large females. Black spots on the caudal fin are sometimes the designating factor of male V. muralis, and an elongated spot is normally found on male specimens of V. sexguttata. No overall size-related color differences have been noted in any specimens of Valenciennea, but juveniles will usually have a considerably more pale coloration than the adults. Also, its stripes and spots continually darken as the fish ages into adulthood. However, adults of V. muralis and V. longipinnis eventually lose their spots located along the mid-lateral body stripe.

In the Wild

Valenciennea species are well represented throughout the entire Indo-Pacific. The most widespread species is V. strigata, which incidentally happens to be the most commonly imported member of the genus. This species can be found from Zanzibar and south along the African coast to as far west as Tahiti and Tuamotu Archipelagos. Taiwan, in the north, and the cooler water off the southern coast of Australia constitute the extreme latitudinal distribution of this species. Along with V. strigata several other species (V. sexguttata, V. wardii, V. helsdingenii) can be located along the eastern African coast. Several members (V. sexguttata, V. puellaris, V. wardii, and V. immaculata) inhabit the Red Sea, but the furthest northern distribution belongs to V. wardii and V. helsdingenii at the southern coast of Japan. Valenciennea strigata represents the furthest southern distribution, and V. wardii also inhabits these same waters. In addition to the vast distribution of some of the members, V. decora (eastern Australia and New Caledonia), V. persica (Persian Gulf), and V. bella (Ryukyu Islands and the Philippines) are localized endemics. Lastly, V. alleni is only known from the turbid waters of the coastal Australian reefs.

Although the distributions of some species overlap, in most cases species do not share the same local microhabitat. Some Sleeper gobies differ by their preferred substrate, others choose different depths. In either case, intermixing of species in not common. In the rare circumstance that intermixed Valenciennea species were noted, V. parva was always noted as being present (Hoese and Larson, 1994).

Within the aforementioned Indo-Pacific waters the Sleeper Gobies inhabit sandy, or sometimes muddy, flats along the base of corals. Most often these are shallow water fish, but researchers have collected specimens from waters reaching 100 feet of depth. On these chosen flats male/female pairs will dig their own burrow(s), excavating sand from underneath rocks. Oftentimes the entrance to the burrow is lined with small pieces of rubble or shells while sand is piled over the top of the rocks or shells that were used as the roof. In some instances a shell is used as a door to the burrow entrance and is moved to the side of the burrow when they exit, and obviously pulled back over the entrance to "close the door" upon retiring for the evening. Valenciennea strigata reportedly has used clumps of calcareous alga for this purpose (Hoese and Strasberg, 1960).

In addition to providing overnight shelter, the burrows are used as protection from danger. However, when threatened both specimens of the pair do not return to the same burrow. One specimen makes a dash into the burrow, while the second member of the pair acts as a decoy and swims off in an opposite direction and generally hides thereafter until the danger has passed.

Feeding is done in pairs, however both members of the pair do not feed at the same time. Instead, one member will forage the surrounding area, extending up to a meter or more from the burrow, while the second member will hover nearby keeping a close eye out for danger. On a regular and frequent basis, the pair will switch roles. In this manner both fish will have plenty of opportunity to eat. By swallowing a mouthful of sand the Sleeper gobies begin the process of eating. The goby will dig down roughly 1.2" into the sandbed when scooping up sand (Michael, Coral Realm). Once the fish has a mouthful of sand, it begins to slowly expel the sand out the gills. The sand falling from the gills has been carefully sifted for any small invertebrates. Of course, any invertebrate the fish is able to sift from the sand is then consumed. Generally, copepods (about 60% of the diet), amphipods, ostracodes, nematodes, and shelled protozoa (foraminiferans) are the main target of consumption. Naturally, once all the sand has been expelled from the mouth, the fish will repeat the process. On at least one occasion this has been observed to be roughly four mouthfuls of sand per minute (Michael, Coral Realm). This feeding technique has garnished these gobies with a second, less commonly used name, the Sand Sifting Gobies.

Like everything else in this genus, spawning is done in pairs. Pairs remain monogamous unless or until the female finds a larger male, in which case she deserts her previous male companion. Males have also, on occasion, deserted the female companion for a larger female. It is presumed a larger male can excavate more sand while a larger female can produce more eggs; each characteristic making the bearer more appealing to the opposite sex. Spawning schedules are highly variable, from V. longipinnis spawning only from April through September, to V. strigata spawning every thirteen days and not following the lunar cycle whatsoever.

In the Home Aquarium

Placing a Sand Sifting Goby into your home aquarium can be a mixed "bag of worms." Depending on the aquarists' philosophy, these gobies are either a gift from the heavens, or a curse from the devil himself. The philosophy that I am referring to is the regarding sandbeds. This is rather simple, actually: If you want an active, "live" sandbed, you do not want a Valenciennea. They will actively prey upon any life form that aquarists would consider beneficial to a healthy live sand bed. Are you curious to what extent they will consume sandbed life? Take this into consideration: In the brutal, eat or be eaten world of reefs, these fish venture over one meter from the security of their den into the vast open world of danger to find food. They would not vacate their burrow by such a distance unless absolutely necessary. Essentially, they prey upon a square meter's worth of sand for food, or in aquarium terms, slightly larger than a sandbed of 5' x 2'. However, they do not have only one burrow. Numerous burrows are constructed over defended territories, sometimes ranging in scope of up to 5000 square feet (Michael, Coral Realm). Lest we not forget, these multiple feeding grounds are also attached to the world's largest refugium.

For those hobbyists that are not concerned with an active sandbed, you are still not in the clear, yet. These sand sifters will do an excellent job of overturning your sand and generally keeping it clean. However, you must realize that they are also indiscriminate dumpsters. That is, they have no worries over which coral they expel the sand onto - and yes, they will mock you and bury all of your corals…daily.

So you don't want a live sandbed, and you don't keep corals? Great, keep reading. Valenciennea are fantastic aquarium fish! That is, they are highly disease resistant and are rather easily fed most any prepared aquarium foods, though it should be geared towards the diet of a carnivore, to supplement their endless excavation for live food. However, there is one stipulation: these gobies build extensive burrows to the point of not being possible in most home aquariums. One researcher required over 1.5 gallons of poly resin to cast one burrow of a V. strigata, the largest burrow of all recorded Valenciennea species. Luckily for hobbyists these fish are so incredibly hardy that they generally do not stress about the lack of an enormous burrow, provided they still have somewhere to hide. If your sandbed will not allow for the fish to construct a burrow of its own, provide one for it either by creative aquascaping, or by physically creating one with any of the several recipes for faux DIY live rock. Please note they prefer a front and back door to their burrow.

What discussion of fish would be complete without talking about aquarium size? You may have noted earlier that these gobies can defend an area approaching 5000 square feet (V. longipinnis), although most species defend a much smaller area. Obviously we cannot recreate this in the typical home aquarium. Thankfully, these fish are not active swimmers, only active feeders. Likewise, they are not terribly aggressive in aquariums and generally get along well with most tank mates. Exceptions to this would include any open water, active swimming fish. When an open water swimmer is forced to constantly cruise past the gobies, it will force them to remain closer to their burrow, and not allow them to display their natural feeding habits.

Compatibility chart for Valenciennea:

Fish	Will Co-Exist	May Co-Exist	Will Not Co-Exist	Notes
Angels, Dwarf	X			Should be an excellent choice.
Angels, Large		X		Large Angels will keep the gobies tucked closer into the rockwork.
Anthias	X			Should be an excellent choice.
Assessors	X			Should be an excellent choice.
Basses	X			Should be an excellent choice.
Batfish	X			Should be an excellent choice.
Blennies	X			Should be an excellent choice.
Boxfishes	X			Should be an excellent choice.
Butterflies	X			Should be an excellent choice.
Cardinals	X			Should be an excellent choice.
Catfish	X			Should be an excellent choice.
Comet	X			Should be an excellent choice.
Cowfish	X			Should be an excellent choice.
Damsels		X		Some damsels can become extremely aggressive.
Dottybacks		X		Some dottybacks can become extremely aggressive.
Dragonets			X	Food competitors; best to not mix.
Drums	X			Should be an excellent choice.
Eels		X		Some eels may consume gobies.
Filefish	X			Should be an excellent choice.
Frogfish			X	May consume gobies.
Goatfish	X			Should be an excellent choice.
Gobies	X			Should be an excellent choice.
Grammas	X			Should be an excellent choice.
Groupers		X		Adults can consume gobies.
Hamlets	X			Should be an excellent choice.
Hawkfish	X			Should be an excellent choice.
Jawfish		X		Sleeper Goby is likely to harass Jawfish.
Lionfish		X		Adults can consume gobies.
Parrotfish	X			Should be an excellent choice.
Pineapple Fish	X			Should be an excellent choice.
Pipefish			X	Best kept in a species dedicated aquarium.
Puffers		X		Some Puffers are likely to harass gobies.
Rabbitfish	X			Should be an excellent choice.
Sand Perches		X		Become aggressive and territorial as they age into adults.
Scorpionfish		X		Adults can consume gobies.
Seahorses			X	Seahorses are best kept in species dedicated aquariums.
Snappers			X	May consume gobies.
Soapfishes			X	May consume gobies.
Soldierfish			X	May consume gobies.
Spinecheeks	X			Should be an excellent choice.
Squirrelfish		X		May consume gobies.
Surgeonfish		X		Surgeonfish will keep gobies tucked closer to rockwork.
Sweetlips		X		Generally should be OK, but adults can consume gobies.
Tilefish	X			Should be an excellent choice.
Toadfish			X	May consume gobies.
Triggerfish		X		Most Triggers are too aggressive to house with gobies.
Waspfish	X			Should be an excellent choice.
Wrasses	X			Should be an excellent choice.

Note: While many of the fish listed are good tank mates for Valenciennea species, 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.

The remaining two issues concerning captive care would have to be feeding requirements, and aquascaping. Starting with aquascaping, you must ensure it is stable. The endless digging of the gobies can cause unstable rock stacks to tumble over. Perhaps the best option would be to keep the fish in a shallow aquarium and not stack the rocks onto one another. Feeding is generally easy, thanks to the appetite of these large gobies. Stick with a variety of any of the commercially available carnivore diets, and feed no less than twice daily. Since these fish are sand sifters, internal parasites can be a common problem. A positive identification of intestinal worms would require a microscopic examination of its fecal matter, or the liver, intestines, or abdominal cavity of deceased fish. Obviously, this is beyond the capabilities of most hobbyists, so it is best to presume the fish has intestinal worms. This presumption is not without merit, however, as an estimated 75 - 85% of imported marine fish have intestinal worms (Bassleer, 1996). The induced stress from poor shipping practices exacerbates this ailment, likely leading to the death of the animal. Normal signs indicative of internal worm infestations are: weight loss while a healthy appetite is present, scraping or flashing against rockwork or sand, and finally, loss of appetite occurring just prior to death. Treatment for internal worms must be administered to a fish that is eating. Live foods are best, as this allows "gut loading," which is the practice of feeding live foods additional vitamins or medicines just prior to feeding. If live foods are unavailable, the next best option is to use freeze-dried foods. The dry food will soak up and retain a majority of the medicine. Piperazine is a good first choice for treatment. Add 250mg per 100g of food each day for a period of 10 days. Praziquantel or lecamisole can be used as a second choice, with the same dosage and time frame. Niclosamide can also be used at 500mg per 100g of food for 10 days (Bassleer, 1996).

It is highly advisable to keep these gobies as pairs in the home aquarium as single individuals are typically noted to succumb to an early death. Spawning of paired individuals is not uncommon in the home aquarium. The eggs, usually between 1000 and 2000 eggs, will be attached to the roof of the burrow. The female will stay in the burrow with the eggs until they hatch, reportedly from one to four days for V. strigata (Michael, Coral Realm) and three weeks for V. sexguttata (Baensch, 1994), while the male remains outside the cave, presumably guarding the female and the eggs from danger. When the eggs hatch the male will seal the burrow entrance with the female inside until nightfall, at which time the male opens the burrow door and along with the female, herd the fry into the open water column (Baensch, 1994).

Meet the Species

Although there are 15 species in the genus, very few actually end up in retail outlets. The most popular species is Valenciennea strigata, or the Golden Head Sleeper Goby as they are commonly referred to at the fish stores. They are also very large for a goby, regularly reaching over seven inches. These fish are generally common in shallow waters where they clearly prefer coarse sand or rubble as the substrate. To illustrate their exceptional digging skills, these fish are capable of constructing a completed burrow by removing 1.5 gallons of sand in less than 30 minutes (Michael, Coral Realm).

Another common import is V. puellaris. The most commonly used name when referring to these fish is the Orange Spotted Sleeper Goby, which for obvious reasons is a fitting name. As was noted above this species has a highly variable coloration, but nonetheless all color variations render a beautiful fish. This species is just as likely to be found on white sand, as it is on black volcanic sand. The combination of black sand and the white fish with orange spots makes for an attractive species display aquarium.

The remaining common import is perhaps also considered the crown jewel of the genus. The Red Sea native (among other locales), V. wardii, also called Ward's Sleeper Goby, unfortunately is noted for being a sensitive fish. It generally does not handle shipping well, and even once acclimated it will remain on edge, always hiding at the slightest disturbance. Using a darker substrate may help ease the fear of a new home, as they tend to prefer darker colored substrates in the wild. It is one of the smallest Valenciennea, barely reaching five inches at adulthood.

Conclusion

The Sand Sifting gobies certainly live up to their given name, and in doing so can make an interesting addition to some home aquariums. Their unique eating behavior is certainly something not seen too often, and possibly thankfully so. The eating behavior can become terribly destructive when the fish is placed into the wrong setting. Ignoring the advice given above will yield results that will make for both unhappy hobbyists and corals.

References:

Baensch, H.A. 1994. Baensch Marine Atlas, Volume 1. Microcosm. Shelburne. 1215 pp.

Bassleer, G. 1996. Internal Worm Infections. Diseases in Marine Aquarium Fish. Bassleer Biofish, Statiostr. Westmeerbeek, Belgium. Pp. 72 - 75.

Burgess, W.E., et al. 1991. Dr. Burgess's Mini-Atlas of Marine Aquarium Fishes MinEdition. T.F.H. Publications. Neptune City. pp.

Hoese, Douglas and Larson, Helen K. 1994. Revision of the Indo-Pacific Gobiid Fish Genus Valenciennea, with Descriptions of Seven New Species. Bern. Pau. Bis. Mus. Honolulu, Hawaii. 71pp.

Lieske, E. and Myers, R. 1996. Coral Reef Fishes. Princeton University Press. Princeton pp. 101.

Michael, S.W. 1998. Reef Fishes Volume 1. Microcosm. Shelburne. pp. 624.

Michael, S. W. 1999. Gobies. Marine Fishes: 500 + Essential-To-Know Aquarium Species. Microcosm. Shelburne. pp. 351, 352.

Smith, Lavett L.and Knopf, Alfred A. 1997. National Audobon Society: Field Guide to Tropical Marine Fishes. New York. p. 615.