COWFISH AND BOXFISH
By Jim Wolf, Marine Biologist.
The 30 plus species of cowfish and boxfish are unmistakable. Members
of the family Ostracionidae lack pelvic fins and slowly cruise over the
reef grazing upon algae and other encrusting organisms. In captivity, put
them a well established aquarium with lots of algae and frequently feed
them Romaine lettuce and mysis. They are not too competitive and are essentially
defenseless, so place them into an aquarium with other slow feeding species.
Acclimate them slowly and insure that there are no intakes for filters
that are too rapid or equipment placed too close the glass as they may
get stuck and become injured or die. Remove any stressed or dead specimens
quickly, as they can exude a toxic compound that may kill other fish (
although this extremely rare and only documented in the Blue Boxfish from
They are prone to Lymphocystis ( a usually harmless viral infection
that looks like small warts, common on the fins), so keep the water clean
to minimize chances of an outbreak. Despite all of the difficulties they
are quite hardy as their slow movement make them easy to capture and hence
they arrive in the fish store in good shape.
Three genera are common to the hobby.
Lactoria The 4 horned cowfish is so named for the four
conspicuous horns protruding from its trunk shaped body. Look closely at
the horns and insure that they are fully sheathed and free from infection
( the horns are prime site for Lymphocystis). Their box shaped body hides
the fact that their belly may be empty. If the eyes are shrunken or sullen,
or if the fecal material is white and stringy, try to boost their diet
with some blanched Romaine lettuce and lots of mysis (let them eat their
Ostracion These are often called cubicus boxfish
for they lack any prominent spines and are very "cuboidal" in shape. These
species are very finicky and are among the species most likely to extrude
ostracitoxin; a possible poison for other tank inhabitants. These delicate
specimens are best kept in a non competitive reef aquarium.
Lactophrys These cowfish resemble a composite of the above
two. They are roughly cube shaped with small reduced horns and a prominent
ridge running along their back. They are quite hardy, and share similar
care to 4 horned cowfish to which they are closely related.