Breeding Ancistrus hoplogenys (L181)

Breeding the black bristlenose Ancistrus hoplogenys (L181): sexing by head tentacles, cave spawning and male brood care following the documented Ancistrus pattern.

Overview

Ancistrus hoplogenys is a bristlenose loricariid catfish that, according to Wikipedia, occurs in South America in the Amazon, Essequibo and Paraguay river basins and grows to about 15.8 cm SL. It was described by Gunther in 1864 and is listed as Least Concern by the IUCN. Species-specific spawning reports are limited, so the account below follows the documented breeding biology of the genus Ancistrus.

Sexing

In Ancistrus, adult males display prominent fleshy tentacles on the head, while females may possess tentacles only along the snout margin and these are smaller. Males also develop evertible cheek odontodes that are less developed or absent in females.

Breeding Setup

Ancistrus species breed in hollows, caves and mud holes in banks, so the breeding tank should provide enclosed caves as nest sites. As genus members are native to flowing-water habitats, well-oxygenated water with good movement supports spawning.

Spawning Behavior & Trigger

Males prepare the nesting site and court females by expanding the dorsal and caudal fins. Research cited by Wikipedia suggests the head tentacles may act as a fry mimic to attract females, allowing males without eggs in the nest to compete.

Egg & Fry Care

Females deposit 20-200 adhesive eggs, usually onto the ceiling of the cavity. The male handles all parental duties, cleaning the eggs and fanning them with his fins to maintain oxygen flow. Eggs hatch within 4-10 days and the male guards the hatchlings for a further 7-10 days.

Common Challenges

Despite a common hobby belief, Wikipedia notes there is no scientific evidence that Ancistrus feed on wood; their natural diet is algae, aufwuchs and detritus, so conditioning and rearing should centre on these foods rather than relying on wood as nutrition.