A small genus of labrid fishes is regularly
among the most popular fish for small marine aquariums. Although
the genus lacks a common name, I'll refer to these regularly
imported and sometimes misunderstood fish as "The Lined
Wrasses" for reasons that should be obvious, once you
get a chance to view a few photos. These small colorful wrasses
have attractive patterns, mostly consisting of horizontal
stripes, although one species has vertical stripes and one
lacks stripes entirely. In addition to their small size and
attractive looks, they are active fish. But are these personable
fish right for every aquarium? Welcome to the August edition
of "Fish Tales" and a look at the genus Pseudocheilinus.
A Six-Line Wrasse, Pseudocheilinus hexataenia, seen
here foraging on fauna
among live rock. Photo courtesy of Lisa Page.
Meet the Family
Pseudocheilinus is one of 60 genera
within the Family Labridae, one of the largest reef fish families,
which contains over 500 species and is second only to Gobiidae
in total number of species. All wrasses, with the exception
of Conniella apterygial, swim with their pectoral fins
(Michael, 1998).
Within the recognized nine subfamilies
of Labridae (Norman, 1957) is the subgroup or "tribe"
called the Cirrhilabrini. Six genera are members of this tribe,
of which Pseudocheilinus is one. All six of these genera
(see below) share a unique eye structure, which is limited
to these genera. This "double pupil" is the result
of a division of the scleral cornea, which creates two equal
halves (Springer and Randall, 1974). It is hypothesized that
the anterior portion may well serve as a macro lens of sorts,
which might aid these fish in the predation of small benthic
invertebrates (Randall, 1999).
Genera of the tribe Cirrhilabrini
Cirrhilabrus
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Pseudocheilinus
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Conniella
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Pseudocheilinops
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Paracheilinus
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Pteragogus
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In addition to the specialized pupil, the
seven members of Pseudocheilinus are characterized
as having three or four pairs of recurved canine teeth on
the anterior position of the upper jaw. The lower jaw has
a single pair of canines up front, and then a series of small
conical teeth on the inside. As can be expected, the design
of the jaw structure aids in the capture of prey.
Originally, there was little confusion
within the genus. The hardest part in reconciling this confusion
seemed to be the problem with obtaining specimens of these
often-secretive reef dwellers. Once the use of ichthyocide
rotenone was established within the scientific community,
knowledge of this genus increased greatly. Bleeker (1857)
originally described Cheilinus hexataenia and later
(1862) reclassified it as Pseudocheilinus. The genus
remained monotypic until Jenkins (1901) described P. octotania
and shortly thereafter Jordan and Evermann (1903) described
P. evanidus. Quite some time passed before a new addition
was recognized. In 1960, Schultz, et. al. described P.
tetrataenia. This, apparently, is where the understanding
of this genus became complicated. In 1970 Randall collected
three additional species of Pseudocheilinus. However,
it took 29 years for them to be officially recognized. The
delay was a result of confusion over what is now known as
P. octotaenia (Randall, 1999).
Randall wasn't sure if this species was a single species
of variable color patterns or more than one species. At the
present time it is considered a singular species with numerous
color patterns.
§citrinus |
§dispilus |
§evanidus |
§hexataenia |
§ocellatus |
§octotaenia |
§tetrataenia |
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In the Wild
All seven species are represented within
Indo-Pacific waters. Geographical distribution varies greatly
amongst the species, with P. hexataenia having the
widest range: from the Red Sea and eastern African coast stretching
across the entire Indian Ocean and into the South Pacific
to Tahiti and Tuamotu Archipelago. Pseudocheilinus evanidus
has a distribution nearly as large, stopping just short of
the Tuamotu Archipelago at the Marquesas Islands. On the flip
side of the coin is P. dispilus, which has a distribution
limited to Mauritius and Reunion Islands. Even though some
specimens of this genus have been found down to 180 feet deep,
most are found in water shallower than 60 feet deep. The exception,
however, is P. ocellatus which is not found above 60
feet, and is only rarely noted above 100 feet of depth (Randall,
1999).
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Pseudocheilinus ocellatus is considered by most as
the most beautiful of all Lined
Wrasses. In recent times it has become more widely available
with a reduciton of price.
Photo courtesy of Henry C. Schultz III.
All species of Pseudocheilinus are
coral reef dwellers. These small wrasses remain secretive
and are rather difficult to approach underwater. They quite
effectively hide in the small nooks and crannies created within
a reef structure. Their main defense is simply to disappear
within the rockwork. They will wedge themselves within this
rockwork and remain hidden until the perceived threat is no
longer a concern. The rockwork is also used as their sleeping
quarters. All Pseudocheilinus spp. are diurnal, spending
the evening inside a mucus cocoon, much like the fishes in
the family Scaridae. This cocoon has been theorized to protect
the entombed fish from predators while they sleep. Beyond
providing a secure retreat, the reef structure also provides
the prey for these wrasses. They are very effective predators
of microfauna. Gut analysis of this species has revealed the
staple of their diet to be small benthic crustaceans, such
as copepods and amphipods. Isopods, small fish, crabs, shrimp,
and polychaetes were also regularly noted in most species.
Individuals of Pseudocheilinus species
are not only shy, but they are also solitary. Some adults
may form loose aggregations, but even still, they do not interact
as groups or harems, instead choosing to remaining a unsociable.
Spawning reports seem to be non-existent, although it is presumed
mating is done in pairs. Pseudocheilinus species are
protogynous hermaphrodites, that is, all males were first
functioning females. Various studies have been performed and
have indicated overall size is a good indication of the sex
of the animal. Generally speaking, a Pseudocheilinus
that is one-third or less of its maximal expected length is
still immature and does not have a sex. Animals between one-third
and two-thirds of their expected adult total length are sexually
functioning females, and thus, males are those individuals
that are above two-thirds of their total expected adult length
(Randall, 1999).
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A wonderful photograph of the Four Line wrasse, Pseudocheilinus
tetrataenia, in
a home aquarium. Photo courtesy of Greg Rothschild of Mother
Nature's Creations.
In the Home Aquarium
All Pseudocheilinus species make
hardy additions to a reef aquarium. They remain extremely
disease resistant, and once established inside an aquarium,
are generally long-lived. Reports of Lined Wrasses living
over 10 years are not uncommon. However, it is also not uncommon
for these diminutive fish to become rather boisterous to the
extent of becoming hostile. Once established in the aquarium,
mixing additional fish, or even shrimp, can be an exercise
of futility. Smaller fish may be consumed, while fish of equal
size or slightly larger are likely to be harassed. Sometimes
the harassment will subside after a few days, other times
it will continue until the death of the targeted animal. In
either case, it is best to take steps to avoid this confrontation.
Some tips to minimize these problems would include adding
the Lined Wrasse last, separating individuals with egg crate
material until aggression has subsided, and designing the
aquarium's aquascape to contain a lot of hiding places. In
some cases the removal of one of the fish may be required
to restore equilibrium. Maintaining individuals of two or
more Pseudocheilinus species in the same aquarium is
not recommended.
Compatibility
chart for Pseudocheilinus:
Fish
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Will Co-Exist
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May Co-Exist
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Will Not Co-Exist
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Notes
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Angels, Dwarf
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X
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Should mix well provided angel is in first.
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Angels, Large
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X
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Good tank mates.
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Anthias
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X
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X
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Individual Anthias are at risk of harassment.
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Assessors
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|
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X
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Wrasse will likely continually pester them.
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Basses
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X
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Good tank mates.
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Batfish
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X
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Good tank mates.
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Blennies
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X
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Most blennies can 'hold their own.'
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Boxfishes
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X
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Good tank mates.
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Butterflies
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X
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Good tank mates.
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Cardinals
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X
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Cardinals in first, but wrasse may harass anyway.
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Catfish
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X
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Good tank mates.
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Comet
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X
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Good tank mates.
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Cowfish
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X
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Small Cowfish are at risk of harassment.
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Damsels
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X
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Good tank mates.
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Dottybacks
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X
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Good tank mates.
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Dragonets
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X
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Food competitors and Lined Wrasse will likely continually
pester them.
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Drums
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X
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Good tank mates.
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Eels
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X
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Some species will mix; Larger specimens may consume
Lined Wrasses.
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Filefish
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X
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Good tank mates.
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Frogfish
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X
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Larger specimens may consume Lined Wrasses.
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Goatfish
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X
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Good tank mates.
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Gobies
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X
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Wrasse will likely continually pester them.
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Grammas
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X
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Wrasse will likely continually pester them.
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Groupers
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X
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Larger specimens may consume Lined Wrasses.
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Hamlets
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X
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Good tank mates.
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Hawkfish
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X
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Good tank mates.
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Jawfish
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X
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Wrasse will likely continually pester them.
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Lionfish
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X
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Larger specimens may consume Lined Wrasses.
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Parrotfish
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X
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Good tank mates.
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Pineapple Fish
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X
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Good tank mates.
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Pipefish
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X
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Food competitors and Lined Wrasses will likely continually
pester them.
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Puffers
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X
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Good tank mates.
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Rabbitfish
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X
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Good tank mates.
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Sand Perches
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X
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Large Sand Perches can consume Lined Wrasses.
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Scorpionfish
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X
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Larger specimens can consume Lined Wrasses.
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Seahorses
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X
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Food competitors and Lined Wrasses will likely continually
pester them.
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Snappers
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X
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Good tank mates.
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Soapfishes
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X
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Good tank mates.
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Soldierfish
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X
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Good tank mates.
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Spinecheeks
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X
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Good tank mates.
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Squirrelfish
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X
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Good tank mates.
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Surgeonfish
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X
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Good tank mates.
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Sweetlips
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X
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Larger specimens can consume Lined Wrasses.
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Tilefish
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X
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Should be excellent tank mates.
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Toadfish
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X
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Larger specimens can consume Lined Wrasses.
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Triggerfish
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X
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Some Triggerfish require a species-specific aquarium.
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Waspfish
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X
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Larger specimens can consume Lined Wrasses.
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Wrasses
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X
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Will harass most other wrasses, the exception being
larger, more aggressive wrasses.
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Note: While many of the fish listed are
good tank mates for Pseudocheilinus
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.
Pseudocheilinus hexataenia, the Six-Line Wrasse, has
the most wide-spread
distribution of the genus. Photo courtesy of Greg Rothschild
of Mother
Nature's Creations.
Besides harassing decorative shrimp, individuals
of Pseudocheilinus species are likely to pester crabs.
In regards to the ornamental shrimp and crabs, it may be too
late by the time you notice the damage being done. Both shrimp
and crabs make up a small portion of their natural diet; so
do not be surprised when they come up missing in a Lined Wrasse
aquarium. It might be in your best interest to plan on not
keeping these mobile invertebrates in combination with a Lined
Wrasse. Also, the commensal crabs often found associated with
Acropora species are likely to be hunted and consumed.
Quite frequently, the fish will ignore these decorative mobile
invertebrates for years, only to decide one day that they
look like a tasty morsel. Once a Lined wrasse becomes a shrimp/crab
eater, it can be expected to remain as such throughout its
life. It would be wise to forego the thought of maintaining
these invertebrates or remove the wrasse. The attacks on mobile
invertebrates likely stops there, with the exception being
small snails that are brave enough to venture out during the
day. Typically, no predation is displayed upon sessile invertebrates.
Of course, before worrying about whether
it will mix with your planned inhabitants, it would be wise
to visually inspect the health of the prospective fish. Avoid
any fish with obvious signs of damage, especially around the
mouth or fins. Likewise, ensure the fish is eating. Lined
Wrasses should be alert and active in the dealer's aquarium,
and should be feeding by actively searching the substrate
and rockwork, as well as taking prepared foods from the water
column.
Naturally, ensure your aquarium meets the
requirements for successful husbandry. Aquarium size is not
terribly important given the small size and shy nature of
these fish. However, the aquarium must be large enough to
meet several criteria. First, it needs to contain adequate
hiding spaces. Lined wrasses are not outgoing fish, and will
likely spend a great deal of time cruising through the live
rock. Small caves, nooks, and crannies should be plentiful.
Aquascape the aquarium to maximize the hiding places, given
the amount of live rock at hand. In addition to hiding places,
a high quality live rock will provide a good deal of natural
foods. In situations where minimal live rock is present, these
pod-hunters will decimate your small benthic invertebrate
population in short order. Supplemental feeding should be
increased and food competitors should be eliminated. These
feedings should be focused around meat-based foods such as
Mysis, plankton, enriched Artemia, and any other
frozen/thawed or freeze-dried foods available to the aquarist
that are geared towards carnivores. Lastly, smaller aquariums
likely contain small fish like gobies, or fish that maintain
minimal territory requirements such as jawfish. However, be
advised that it is these same fish which the Lined wrasses
are most likely to pester. Therefore, choose aquarium inhabitants
carefully.
Meet the Species
By far the most popular Pseudocheilinus
is P. hexataenia, or the Six-Lined Wrasse. The relatively
shallow water they inhabit, combined with their easily explains
why they are the most regularly available Lined wrasse. Most
are located above 40 feet of depth, with the majority located
shallower than 10 feet on some reefs.
The diet of this species is widely variable,
with stomach contents containing such items as foraminifera,
copepods, amphipods, gastropod eggs, gnathiid and idoteid
isopods, shrimp and shrimp larvae, and mysids. Sano, et al.,
(1984) concluded this species consumes mainly demersal planktonic
crustaceans, but feeds occasionally on crustacean ectoparasites
of other fishes.
The largest specimen studied thus far has
been 61mm. For those concerned about the sex of their fish,
all specimens measuring 35mm and up were determined to be
males, those in the 25 - 30mm range were mature females, and
those in the 21 - 27mm range were immature (Randall, 1999).
This obviously lends support to the belief of protogynous
hermaphroditism.
The Four-Lined wrasse, P. tetrataenia,
is another regular import. Distribution is throughout both
the tropical North and South Pacific Oceans. Like the Six-Lined,
it is a shallow reef dweller. It prefers to stay tight to
the outer reef slopes and is most often found associating
with the coral Pocillopora meandrina (Randall, 1999).
Rarely does this species venture more than several inches
to one foot above the substrate. Stomach contents of this
fish were also highly variable, though somewhat selective.
One fish was noted to have only the remains of a Pistol Shrimp
(Alpheus sp.), while another contained a crab, and
yet a third had only shrimp and gastropod larvae.
Pseudocheilinus tetrataenia held
true to protogynous hermaphroditism when researched. The largest
individuals (up to 102mm) were always male, the smallest were
immature, and those in the middle were female. Interestingly,
one specimen that was 42.5mm had the tissue of both the female
reproductive organs as well as that of the male (Randall,
1999).
Another Pseudocheilinus tetrataenia in the home aquarium.
They adapt well to the high
light aquariums of today thanks to their tendancy to prefer
shallow outer reefs. Photos
courtesy of Greg Rothschild of Mother
Nature's Creations.
The Eight-Lined Wrasse, or P. octotaenia,
is not nearly as regularly imported as the two aforementioned
Lined wrasses. These are among the largest Lined wrasses,
roughly 127mm at adulthood, and consequently their diet reflects
this. Stomach contents revealed two specimens dining exclusively
on small fish, another on crabs, and a third split between
shrimp and gastropods (note, I did not say 'larvae'). This
species is rather variable in color patterns, and at one point
some confusion existed because of the multi-color patterns.
Originally named by Jenkins (1901), it was subsequently renamed
by Smith (1955) as P. margaretae. Schultz (1960) moved
P. margaretae into synonymy with P. octotaenia.
The Five-bar Wrasse, or P. ocellatus,
is likely considered the most attractive of all the Pseudocheilinus.
Distribution is sporadic throughout the tropical North and
South Pacific Oceans and is generally limited to deeper waters
than the common Lined wrasses inhabit. Most specimens are
located from 90 to 120 feet of depth. Their sporadic distribution,
combined with the depth at which they are acquired, combine
to make this Lined wrasse the most expensive of the genus.
Four inches of length at adulthood should be expected for
these wrasses.
Conclusion
Oftentimes hobbyists are excited upon seeing
their first Lined wrasse. Their small size and adorable stripes
usually make for a quick impulse purchase. They mistakenly
assume it'll mix well into any aquarium, and eagerly take
it home. Only after it becomes aggressive will the hobbyist
do a quick search and discover that this behavior was to be
expected. The hobbyist is then faced with the unpleasant duty
of trying to capture a small, fast, nimble fish. It is not
an easy task! Arming yourself with this knowledge before the
purchase will save many headaches down the road. For those
reading this after their purchase, may I recommend a good
fish trap link?
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