Paracanthurus hepatus has a royal blue body, yellow tail, and black 'palette' design The lower body is yellow in the west-central Indian OceanIt grows to 30 cm (12 in.) This fish is rather flat, like a pancake, with a circular body shape, a pointed snout-like nose, and small scales The blue tang has 9 dorsal spines, 26-28 dorsal soft rays, 3 anal spines, and 24-26 anal soft rays.
As a juvenile, its diet consists primarily of plankton
Adults are omnivorous and feed on plankton, but will also graze on algae Spawning occurs during late afternoon and evening hours This event is indicated by a change in color from a uniform dark blue to a pale blue.
Males aggressively court female members of the school, leading to a quick upward spawning rush toward the surface of the water during which eggs and sperm are released
The eggs are small, approximately 0.8 mm in diameter The eggs are Pelagic, each containing a single droplet of oil for flotation The fertilized eggs hatch in twenty-four hours, revealing small, translucent larvae with silvery abdomens and rudimentary caudal spines
Blue tangs can also, when faced with danger or dark spaces, make themselves semi-transparent, in order to help with evasion and light passivity, respectively.
In Your Aquarium
As juveniles, they require a 40 gallon aquarium, but as adults require a 75 gallon tank They will eat small crustaceans such as mysids and krill Adults nibble algae and nori
Having more than one in a small aquarium can cause stress, which can lead to injury from fighting This fish is reef compatible — will not eat corals or anemones.