Calloplesiops altivelis is widespread in all the tropical Indo-Pacific and is often available on the market.
Calloplesiops altivelis presents a body with a rather extended and quite thin back. Its very extended fins make it optically bigger and its dark surface is saturated with little white spots. The dorsal fin in the ending posterior part shows a big ocular spot.
It reaches 16 centimetres; the female usually remains smaller than the male.
This species leads a rather hidden existence, is territorial and mainly stays in fissures or small cavities, often in the most external part of the reef.
Maintenance in aquarium
These fishes are extraordinarily suitable for a reef aquarium, as long as the latter is correctly structured with passages, fissures and cavities. It is possible to attempt the realisation of hiding places so as to make them inspectable by the aquarist, for example by using a posterior corner of the aquarium obscuring the lateral glass with a removable black cardboard. Calloplesiops altivelis is an ambush predator, which just for this reason is provided with a certain metabolism and is satisfied even with only one feeding per day. Initially it is advisable to feed these fishes in a very targeted way directly inside their shelter, since they are very reluctant to leave the nest at the beginning. However, well-acclimatised individuals quickly learn to approach the hand or the tweezers during the feeding. They look like timid animals, preferring to stay sheltered, but despite being peaceful they are also rich in temperament. They even fight against extremely territorial fishes! It would be appropriate to always breed them in couples, choosing fishes of very different sizes to avoid fights. They are fishes that change their gender from female to male. If a couple has formed, the same remains stable from the gender point of view, at least until the male remains healthy and dominant. If it gets ill or dies, the female changes into a male in a short time.
In nature the Calloplesiops mainly feed on crustaceans. In aquarium they almost immediately accept any kind of frozen food, sometimes even the feed in flakes. If adequately fed, they will almost never attack shrimps or little fishes. On the contrary, these fishes sometimes let themselves be cleaned by shrimps like the Lysmata amboinensis.
Reproduction and behavior
Calloplesiops altivelis, as long as the feed provided is good, regularly engages in reproduction activities. The courting (even in nature!) always happens in a very tempestuous way. Often, the female has to suffer damages to the fins, which however heal within a few days. The lump of eggs is fixed to the upper part of their cavity, and surveilled for the entire period of five, six days until the hatching. The just hatched young fishes, then, no longer benefit from the surveillance of the parent, who however does not intend to devour them. A great amazement is raised by the function of the apparent eye on the fin during the phase of surveillance on the eggs: the male cover them, by continuously standing in front of them with the fins widely spread. In case of disturbance or threat by a predator, it slowly moves backwards in the direction of the danger, showing the false eye that on the whole makes everything very similar to the head of a moray (Gymnothorax meleagris). This behaviour of defence and appearance is part of the most representative examples in this respect (McCosker 1977, Thaler 1997, 2000). These fishes have been reproduced several times in aquarium: H. Wassink (1988) was the first, followed by Blok (1988) and then by W. Mai, even to the third generation. In an unpleasant article of his (Mai, 2001), describes in great detail the difficulties during the administration of food and the raising of the young fishes: he removed the eggs shortly before the hatching, since the just hatched larvae, unlike it usually happens for other fishes, do not swim towards a light source and therefore are difficult to collect. The feeding (the Brachionus are not accepted, while the nauplii of Artemia are only starting from the 16th day) and the techniques to adopt with these young fishes, extremely sensitive to stress, are also described with great attention and should represent for any committed breeder of marine fishes a real challenge!