Blackcap Basslet

The blackcap basslet is recognized by its dark purple or violet body and the sharply defined black "cap" that runs from the snout over the top of the head to the front of the dorsal fin. It is a close relative of the royal gramma (Gramma loreto), which has its own page on this site; it grows larger, reaching about 10 cm.

In the wild it lives deeper than the royal gramma. In the aquarium it is a hardy fish that accepts almost any food and does not harm corals. Aquarium-bred specimens are also available from time to time. It is more expensive and less commonly available than the royal gramma; its temperament is also somewhat tougher.

It lives on steep walls and drop-offs beyond the outer reefs in the Caribbean, the Bahamas and along the coasts of Central America. It is mostly found in waters deeper than 30 meters; between 15 and 30 meters it gradually gives way to the royal gramma. It often swims upside down under rock overhangs and retreats into crevices when in danger.

• Volume: At least 110 liters.
• Water: Salinity specific gravity 1.023–1.026, pH 8.1–8.4, temperature 24–27°C.
• Layout: Plenty of caves, rock overhangs and crevices; overhangs under which it can hang upside down put it at ease.
• Lighting: It is a deep-water fish; provide shaded corners.
• Lid: It can jump; a covered aquarium is recommended.
• Reef compatibility: Reef-safe; it leaves corals and snails alone and lives without problems alongside larger ornamental shrimp.

Carnivorous. Offer frozen mysis, brine shrimp, copepods and granules. It likes catching food from the water column. Feeding small amounts twice a day is enough.

It considers the cave it has chosen its own territory and chases fish that approach it. It is noticeably harsher towards species that share the same cave-dwelling lifestyle, such as the royal gramma and dottybacks. It is usually calm towards other fish.

Good companions: Clownfish, chromis, gobies, blennies, cardinalfish, tangs, wrasses, dwarf angelfish.

Avoid: The royal gramma and other grammas, dottybacks, Liopropoma basslets, large predators.

Kept singly. In a very large aquarium with many caves, a pair or one male with several females can live together, but this is only possible if the individuals are added at the same time. Two males in the same aquarium fight.

In the genus Gramma, the male builds a nest of algae and fine debris inside a cavity; the female lays her eggs there and the male guards them. The availability of aquarium-bred specimens shows that this is possible, but raising the planktonic fry takes expertise.

• Hardy; quarantine a new specimen for 3–4 weeks.
• Marine white spot and velvet: Observe it in quarantine.
• Stress and loss of appetite are seen in aquariums with few hiding places.

Reliable external sexing is difficult. Males are usually slightly larger; a definite distinction can only be made from breeding behavior.