Bank Butterflyfish

Q. I've been keeping marine fish for about 10 years, and am especially interested in butterflyfishes. I have kept many different varieties, but there is one species I have long been interested in acquiring, but I have yet to find — the bank butterflyfish (Chaetodon aya). I was wondering if you could give me some information on this apparently rare fish.

I have a 75-gallon tank that contains some live rock, but no corals, with a trickle filter. What other fish live in the same habitat as the bank butterflyfish? Thanks for your help and keep up the good work!

A. Yes, I can give you some information about the bank butterflyfish and may even be able to help you acquire one of these beauties. This fish is closely related to several deepwater species that have a similar color pattern, prominent dorsal spines that make them unappetizing to most fish-eating predators, and a moderately long snout. In fact, these fish, along with several others, are placed in a separate genus (Prognathodes) by some ichthyologists (Burgess 1978). Other ichthyologists do not regard this as a valid genus, but lower it to subgenus status (Allen 1985).

The members of this group that are most similar to the bank butterflyfish include the threeband butterflyfish (Chaetodon guyanensis), which occurs in the southern Caribbean to the Florida coast, the marcellae butterflyfish (C. marcellae) from western Africa and the scythe butterflyfish (C. falcifer) from the tropical eastern Pacific. All of these species are very rare in the aquarium trade, with most individuals that are collected being sent to Japan, where they sell for many yen!

The first specimen of the bank butterfly was collected in 1880, when a red snapper caught off the coast of Florida regurigitated it onto the deck of a boat. In fact, it was given the species name, aya, because the red snapper was known scientifically at that time as Lutjanus aya (it is now called Lutjanus campechanus by the ichthyologically inclined). The common name of this fish is derived from its preference for deep, offshore banks.

Today, this fish is being regularly collected for the aquarium trade off the southeast coast of Florida. A few have also been collected off the Florida panhandle in the Gulf of Mexico (David Evans, personal communication). The bank butterflyfish prefers deeper water than many of the chaetodontids, and although small individuals are observed as shallow as 80 feet, they do not occur with any regularity until one descends deeper than 150 feet (Bob Rice, personal communication). Of course, diving at these depths limits the amount of time the diver has to actually catch the fish, and requires that the fish undergo lengthy decompression stops on its way to the surface to prevent injury to its gas bladder.

Although most bank butterflys entering the trade are coming from the eastern coast of Florida, it has also been reported from North Carolina south to the Yucatan Peninsula, and has also been observed in the northeastern Gulf of Mexico. Off the North Carolina coast it has been observed regularly from deepwater manned submersibles at depths of 230 to 385 feet (Parker and Ross 1986). The deepest record for this fish is 551 feet (Leiske and Myers 1994)!

The bank butterfly is usually observed singly, near low and high profile reef structures and around ship wreckage (Parker and Ross 1986, Lindquist and Clavijo 1993). Occasionally they are also observed in pairs, or even in loose aggregations (Bob Rice, personal communication). Although no information is available on its food habits, it probably feeds on tube worms and possibly on the polyps of gorgonians or black corals. It grows to 6 inches.

Because they occur in deep water, and relatively few people attempt to collect them, they do command a higher price than the majority of butterflyfishes. They usually retail between $200 to $400 depending on the fish's size and the retailers mark-up. But, unlike many of the less expensive butterflyfishes, this is a durable aquarium species that, if properly maintained, will live for many years in the home aquarium. It will feed on most aquarium foods, including frozen preparations, finely chopped seafood, brine shrimp, freeze-dried krill and even flake food. Usually it takes several days before it adjusts to its new home, but not if kept with more aggressive tankmates that may harass it.

Bank butterflyfish of less than about 2 inches will have a more difficult time adapting to the captive environment than large individuals (Bob Rice, personal communication). More than one of these fish can be housed in the same tank if the tank is large enough (100 gallons or more). They may chase each other occasionally, but rarely inflict harm on one another.

Although this species prefers cooler water (between 61 to 72 degrees Fahrenheit), it can be kept at temperatures of up to 80 degrees (Allen 1985; Bob Rice, personal communication). However, I would recommend keeping it below 75 degrees. Although these fish typically live in lower light conditions, they will acclimate to more brightly lit aquariums.

They are not a good choice for the reef tank because they may nip at soft coral polyps, especially those of gorgonian species. I also know of one bank butterflyfish that began picking at an open brain coral (Trachyphyllia geoffroyi). However, it did not bother any of the other large-polyped stony corals or soft corals in the tank (Bill Gordy, personal communication). They will do great in a tank with live rock, although they will decimate any tube worms that may be present on the substrate.

If you want to set up a community tank that includes fishes that are encountered in the same habitat as the bank butterflyfish, you could include the following species: a wrasse bass (Liopropoma eukrines), creole fish (Paranthias furcifer), twospot cardinalfish (Apogon pseudomaculatus), reef butterflyfish (Chaetodon sedentarius), a juvenile blue angelfish (Holacanthus bermudensis), purple reef fish (Chromis scotti) and the Cuban hogfish (Bodianus pulchellus). For any hobbyists or retailers who are interested in acquiring a bank butterflyfish, I recommend you write me in care of AFI and I will put you in touch with an individual who can collect them for you.