By Bob Goemans
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Prognathodes aya

Jordan, 1886

Bank Butterflyfish, Doubleband Butterflyfish

Not Reef Tank Suitable

Likely Fish-Only Tank Suitable

Range: Western Atlantic Ocean: North Carolina, northern Sea of Cortez to Yucatan in Mexico

Size: 6 inches (15 cm)

Natural Environment: Inhabits deep reef drop offs and sunken ships at depths from about 80 to 380 feet (24 – 115 m) and is thought to feed on tubeworms, gorgonians and black coral polyps. Mostly occurs singly, with adults not often found in waters above 150 feet (45 m).

General Husbandry: This rarely seen in the trade species has a silvery body with a narrow black band over the head to and through the eyes. Theres also a wide vertical black band on the rear of the body, with yellow on all fins except the tail, which is clear.

When available, adapts quite easily to aquarium life in larger peaceful fish-only community aquariums, especially those with lots of open swimming space. A meaty diet of live fortified brine shrimp, black worms (Lumbriculus variegatus), and/or various frozen meaty foods such as mysis, and flake foods, should be offered several times daily.

More than one species from this genus can be maintained in the same aquarium, however, to do so requires at least a 125 gallon aquarium having lots of live rock with caves and ledges to explore, or hide when necessary.

Not safe with LPS corals, soft corals, gorgonians, and tubeworms/feather dusters.

Rarely is there a problem getting this species to feed in the aquarium, however, small human consumption clams/black mussels purchased in local grocery stores and placed on the half-shell in the aquarium will help entice it to begin feeding. Over time, frozen foods like mysis and brine shrimp will be more readily accepted.


    Order: Perciformes

    Suborder: Percoidei

    Family: Chaetodontidae

    Genus: Prognathodes

FYI: Quite attractive, hardy, yet often somewhat expensive because it needs to undergo decompression stops to prevent injury to its gas bladder since its captured in deep waters.

Those in this genus are usually referred to as ‘Longnose Butterflyfish.’

Pressing some soft foods into openings/crevices on a piece of old dead coral skeleton can sometimes encourage finicky eaters to begin feeding.

Experience Level: Intermediate

Temperament: Peaceful

Diet: Carnivore

Coral Safe: No

Invertebrate Safe: No

Acclimation Time: 30 minutes+

Aquarium Environment: Fish-only aquarium

Tankmates: Peaceful or non-aggressive

Minimum Tank Size: 75 gallons

Temperature Range: 61 - 77°F (16 – 25°C)

Specific Gravity: 1.020-1.026

pH: 8.0 - 8.5

 Prognathodes aya (Bank Butterflyfish, Doubleband Butterflyfish)
Photo © Vincent Hargreaves
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Polyp Lab