The Banded butterflyfish is a small-bodied fish that lives on coral reefs of the western Atlantic Ocean. Like all butterflyfishes, the Banded butterflyfish has a discus body and a very small mouth, perfect for biting its preferred prey – small worms and live, soft tissue of reef-building corals. This species gets its common name from the series of dark, vertical bars (or bands) that help to provide it with camouflage. One of the bands always covers the eye, hiding it from potential predators and preventing predators from being able to easily determine which end of the body is the head and which end is the tail.
Though generally considered to be foraging predators, which lazily search the reef surface for food, Banded butterflyfish actually utilize a variety of feeding strategies. Some (often in pairs) do forage on the reef surface. Others form larger schools that visually hunt tiny plankton in the water column above the reef. Still others are known to engage in cleaning behavior, where a larger fish (potentially of a species known to eat Banded butterflyfish) approaches a group of this species in order to be cleaned of parasites. The intricate behaviors that signal that the predator is approaching to be cleaned rather than to attack are not fully understood by fish researchers.
Banded butterflyfish reproduce through a behavior known as broadcast spawning, where a female releases her eggs and a male releases sperm into the water column above the reef, at the same time. This method increases the likelihood that fertilized eggs will not be eaten by egg predators on the reef surface and will instead be carried away by the currents. Unlike in several other species of reef fishes, however, the Banded butterflyfish does not reproduce in groups and instead forms monogamous pairs before this spawning behavior.
The Banded butterflyfish is generally restricted to the Caribbean basin and surrounding waters (Gulf of Mexico, Florida, Bermuda), but individuals are occasionally observed along the coast of New England and even in European waters. In those cases, scientists believe that the observed individuals were carried by strong, warm currents during particularly warm years. Scientists do not believe that they are able to reproduce and form viable, permanent populations in these regions. This species is not eaten by people, but it is captured for display in public and private aquaria. Currently, scientists do not believe that the species is at any risk of extinction, and population sizes are apparently stable. However, it is important to continue to monitor Banded butterflyfish populations in order to ensure that any changes resulting from capture of adults or from expected negative trends in coral reef health throughout its range will be identified at an early stage.