Blue Spot Butterflyfish
(Chaetodon plebius)

The blue spot butterflyfish or Chaetodon plebius is a member of the family Chaetodontidae. They are indigenous to the coral reef systems found in the shallower regions of the Indo-Pacific. The blue spot butterflyfish is commonly referred to as blue-blotch butterflyfish or the coral butterflyfish. The latter name references its dietary habits in the wild.

This fish has a bright yellow disk shaped body with slightly darker horizontal markings and a patch of sky blue on the upper mid-section of its body. It has a single vertical stripe that runs down through its eyes toward the lower part of its body. It also has an “eye spot” where the caudal attaches to its body. This eye-spot is meant to confuse predators. Its real eye is almost camouflaged in the vertical stripe. The blue spot will grow to a length of approximately six inches long.

The blue spot diet consists primarily of coral polyps from the Acropora species which flourish in the shallow water eco-systems native to the blue spot habitat. This fish has also been known to function as a cleaning fish ingesting parasites off of other fish. But it is its specialized dietary requirements that have sparked controversy among ecologists and aquarists around the world.

In fact, whether or not it is even fair to take an animal with such specialized nutritional needs and radically change its diet to transition it into a life of captivity is a subject of heated debate. This fish is notorious for refusing to eat once it has been removed from its natural habitat. It will very often succumb to malnutrition resulting in its eventual death. It has been known to completely ignore the highest quality marine reef foods. It is even argued whether this fish is severely traumatized by its abrupt transition or if it simply does not recognize a foreign source of nutrition. Many conscientious aquarists will avoid this species altogether as a suitable fish for their aquarium.

If you wish to attempt to raise one it is highly recommended that you do not purchase one online unless it comes with a guarantee that it is feeding in captivity. If you buy one locally ask that you be allowed to watch it eat to insure that it has acclimated to aquarium life before taking it home. They have been reported to function just fine in their new environment once they start eating. In nature these fish are typically found in pairs. You might want to take this into consideration at the time of purchase.

Blue spots are carnivorous. In captivity they can be fed vitamin enriched brine shrimp, protein based marine fish food or finely chopped fresh seafood such as shrimp or squid. A feeding blue spot makes a wonderful addition to a community tank. They are a non-aggressive, striking beautiful species that mixes well with fish of similar temperament. A minimum tank size of 75 gallons will suffice. If you are a reef tank owner bear in mind that they may learn to eat your coral as a suitable substitute for their dietary needs. These are mid-water to bottom swimmers in an aquarium setting.

There is no lifespan information available on this specific species, but the family of fish collectively referred to as butterflyfish has an average life expectancy of five to seven years.

Temperature	pH Level	Specific Gravity
72-78  °F	8.1-8-4	1.020-1.025