Blue Spot Butterflyfish (Chaetodon plebius)
The blue spot butterflyfish (Chaetodon plebius) has a mostly yellow body with a blue spot or area toward the upper part of its body. It has a dark stripe running through its eye as well as a dark "eye-spot" located at the junction of its body and caudal fin.
The blue spot butterflyfish belongs to the family Chaetodontidae. It is also commonly called the blue-blotch butterflyfish and the coral butterflyfish.
The black stripes running through the butterflyfish's eyes helps to confuse predators. Predators can't see the "real" eyes of the fish, and confuse the eye spot as the fish's eyes.
In their natural habitat they are found in the Indo-Pacific along coral reefs where they feed on coral polyps (Acropora species). This is why these fish are often referred to as "coral butterflyfish." They also sometimes behave as cleaner fish - feeding on the parasites of other fish.
They are not good fish for reef tanks as they will eat your stony corals.
Blue spot butterflyfish are somewhat difficult to feed in captivity. Apparently once they start feeding they will continue and then do fine, but at first they may not recognize the substitute aquarium fare you give to them as food.
In captivity you may feed your blue spot butterflyfish chopped up seafood (squid, shrimp), mysid shrimp, and meaty frozen foods for marine fish.
One source suggested putting their food on a bleached stony coral skeleton to get them to start feeding (Michael, 2001). I haven't actually tried this and so I don't know if it works or not.
This next may seem like a radical idea, but if your blue spot butterflyfish refuses to eat any of the foods you provide for it, then why not let them eat some Acropora spp. corals? I realize that this idea might seem rather unusual, not to mention expensive, and that it may wreck up the appearance of your reef tank, but if your coral butterflyfish is reluctant to eat other foods it might help them to survive their transition to other aquarium foods.
I'm not sure that we should bring fish species into captivity and then try to radically change their diet anyway. We, as aquarists, often do this. Some fish may do just fine on a substitute diet and others may not.
However, once the blue spot butterflyfish gets acclimated to eating in captivity they tend to do just fine as long as the aquarium water quality is good.
However, if your blue spot butterflyfish refuses to eat then I'd first try serving their food on Acropora coral skeletons as suggested by Michael (2001). If this doesn't work then maybe you could try letting them eat some Acropora corals. Just an idea.
Spotfin butterflyfish reach a maximum size of about 6 inches (15 cm).
They can be housed with other members of its species as well as other similar species, especially if they are all introduced at the same time.
Michael, S. W. (2001). Marine Fishes. Neptune City, NJ: T.F.H. Publications.