Choosing a Butterflyfish

Butterflyfish include some of the most beautiful of all saltwater aquarium fish. Graceful swimmers with striking coloration and shapes, they are among the most popular fish to keep. What they have in beauty, however, they often lack in compatibility and so must be chosen with care.

Butterflyfish, in the family Chaetodontidae, are widely distributed throughout all tropical seas, and like most reef fish, they reach their greatest diversity in the Indo-Pacific. In nature, butterflyfish can grow to be up to nine inches long, depending on the species, although most won’t get much bigger than five or six inches. They are usually thin and disk-like, colored in striking yellows, oranges, blues and greens arranged in patterns of stripes, cross-hatches and spots.

Tank Requirements

Although they are quite shy, butterflyfish can be highly territorial and aggressive and will sometimes injure other fish – particularly their own kind – if they come too close. Because they take such great offense at trespassers, it is important to have enough room in your tank for them to pick and protect their turf. Their unruly behaviors combined with picky eating habits and stringent water-quality needs make them difficult fish for the beginner to keep.

Butterflyfish need water on a par with that of a healthy reef tank, meaning a steady pH of about 8.4, good aeration, good light levels, and low ammonia, nitrates and nitrites. This last requirement is most important. Butterflyfish are highly sensitive to nitrite concentrations and should not be kept in a newly established tank. If you decide to get one of these fish, you must first be sure that you have a well-established tank in which nitrate levels barely fluctuate.


Many species of butterfly fish have their own very particular feeding behaviors, such as feeding only on a single species of coral, and need a small portion of their diet to be vegetable matter such as algae. Most also require some source of meat – shrimp, worms or chopped fish.

Many different kinds of butterflyfish are available in stores. Be careful when you are deciding which one to get; many species have such specialized needs that they will die in the home tank no matter how much care you take with them. Those to avoid are the ornate butterflyfish, Chaetodon ornatissimus, and Meyer’s butterflyfish, Chaetodon meyeri. These usually do not survive in captivity, but there are many to chose from that will.

Most Popular Species

The forcipiger is yellow with varying colorations, usually darker on top, lighter on the bottom. It is omnivorous and will eat brine shrimp, pieces of chopped clams, shrimp and other such food. Its close relative, the true long-nosed butterfly has a longer snout and is more difficult to maintain. The copper-banded butterfly has requirements like those of the forcipiger. It is light in coloration with darker copper-colored vertical bands on its body. It is slightly more difficult to maintain since it prefers live foods such as brine shrimp.