• Butterfly fish often have brightly-colored markings.butterfly fish image by Lucid_Exposure from Fotolia.com
  
  Butterfly fish are tropical marine fish that belong to the biological family Chaetodontidae. There are more than 120 different species of butterfly fish, with individual species having unique, often brightly-colored markings across their bodies. Their name derives from the similarity of these markings to the ones found on butterfly wings.
  
  

Appearance

• On average, butterfly fish range in size from around 4 inches in length to 9 inches. The largest, however, the saddle butterfly fish and the lined butterfly fish, can reach 12 inches. All butterfly fish are distinguished by deep, laterally narrow bodies. Most have striking patterns and markings. Some have large spots on their sides (to confuse predators about which part of the fish to attack), while others have dark bands across their eyes.
  
  

Habitat

• Butterfly fish are found in the Atlantic, Indian and Pacific oceans. They generally habituate waters of less than 60 feet deep, although a few species do dive deeper, up to 550 feet. They are most commonly found on coral reefs. Butterfly fish are territorial with mated pairs claiming an area of the reef as their own and repelling intruders. Butterfly fish are diurnal, feeding during the day and resting in crevices during the night.
  
  

Diet

• The majority of butterfly fish feed on coral polyps, anemones, worms and other reef-dwelling invertebrates. They are equipped with small protruding mouths that are ideally suited to plucking these prey items from coral crevices and rock formations. Butterfly fish have several rows of fibrous teeth that they use for grinding up their food.
  
  

Reproduction

• Butterfly fish will usually mate for life. They reproduce by pelagic spawning--releasing a great number of fertilized eggs into the water, which become part of the plankton layer, a mass of tiny invertebrates, that moves with the ocean currents. They embryos develop and hatch while drifting with the currents. Young butterfly fish go through a stage in which they grow bony plates on their heads. These plates are shed as the fish matures.
  
  

Aquariums

• The striking colors of butterfly fish make them popular features for aquariums. However, their specialized diet is difficult to replicate in captivity, and their territorial instincts can instigate conflict with other species. It is also difficult to breed butterfly fish in captivity.