NEWS112
32
Gobiodonokinawae,
male.
Pair of
G.okinawae,
male in front.
A color variant of
G.histrio
or adifferent
species?
Gobiodonhistrio
a lot of water has a lot less effect than the
same amount of dirt in a small amount of
water. But once you are past the novice
stage and have gained experience in the
tricks of the trade, then there is no longer
any reasonnot to set uponeormore small
aquaria containing 10 - 30 liters of water.
After all, large aquaria have one huge
drawback:small creatures tend todisappear
in them,never tobeseenagain!
Coralgobies
Thisdangerdoesn'tnecessarilyapply in the
case of the coral gobies of the genus
Gobiodon
. But they have a number of
features that make it more interesting to
keepthem inspecialaquariaratherthan ina
large reef aquarium. There are a lot of
species: 27 are currently accepted as valid,
and a number of others are still awaiting
scientificdescription.Virtuallynoneof them
growssignificantly larger than6cm,and the
majorityusuallyattain just2-3cm in length.
Despite their small size they are rather
confident fishes, sometimes little short of
bold. This is because they possess a
poisonous skin mucus that apparently
tastes really horrible. As a result these little
gobies have virtually no predators. In
addition they live with stony corals of the
genus
Acropora
, among whose branches
they find shelter.This isbroadlycomparable
to the symbiosis between clownfishes and
their anemones. In thewild some
Gobiodon
species even have a species-specific link
withparticular
Acropora
species.
Identifying thespecies isdifficult!
Telling the
Gobiodon
species apart is
exceptionally tricky, as fundamentally the
species differ only in their coloration and
that changes in the course of their lives.
Hence it is best to acquire apair right from
the start, if possible, as it may prove very
difficult to buy another individual of the
same species or population at a later date.
And that would be a pity, as
Gobiodon
specieswill evenbreed in theaquarium.
The sexesaren't verydifficult to tell apart in
individuals of the same age, asmales grow
larger and have a bulkier head.Males of
G.
okinawae
also have white cheeks. Because
coral gobies, like so many reef fishes, can
change their sex, any two individuals will
almostalwaysdevelop intoapair.
Cleaningcausesdamage
Suchapairwill,ofcourse,alsobea real sight
to see ina large reef tank.Butunfortunately
Gobiodon
can't
be
recommended
unreservedly, at least not for stony-coral
aquaria, as there is the associated small
problem that they like to snack on the
occasional polyp. That isn't too serious as
Gobiodon
enjoy dry and frozen foods, and
are thus easy to satisfy. But coral gobies
breed very readily in the paradise-like
conditions of the aquarium. And because
they are substrate-spawners, to do so they
clean a spawning substrate to which to
attachtheireggs.Thisspawningsubstrate is,
however, invariably the foot of an
Acropora
,
or, ifno
Acropora
isavailable,thatofanother
stonycoral.Thecoral inquestionmaybe so
badlydamaged intheprocessthat itdoesn't
open any more and may even die. But
removing the tiny gobies is then a total
impossibility,as ina largeaquariumtheycan
be guaranteed to elude every attempt by
the stressed-out coral enthusiast to catch
them.So forthisreasoncoralgobiesarebest
kept and bred in special small aquaria,
where their badhabitswon't benoticeable
and their good ones will be seen to best
advantage!
