Breeding Ancistrus dubius

Breeding the spotted bristlenose Ancistrus dubius: sexing by head tentacles, cave spawning and male brood care following the documented Ancistrus pattern.

Overview

Ancistrus dubius is a bristlenose loricariid from South America. FishBase and Wikipedia record it from the Amazon basin and the middle Parana and Paraguay river basins, with a maximum length of about 12.6 cm SL. FishBase notes the genus is capable of facultative or obligate air-breathing and lists the species as Least Concern. Species-specific spawning reports are limited, so the account below follows the documented breeding biology of the genus Ancistrus.

Sexing

In Ancistrus, adult males show prominent fleshy head tentacles, whereas females have at most smaller tentacles along the snout margin. Males also develop evertible cheek odontodes that are reduced or absent in females.

Breeding Setup

Ancistrus species breed in hollows, caves and bank holes, so enclosed caves should be offered as nest sites. As genus members favour flowing water, well-oxygenated water with movement supports spawning.

Spawning Behavior & Trigger

Males prepare the nest site and court females by expanding the dorsal and caudal fins. Wikipedia notes research suggesting the head tentacles may act as a fry mimic to attract females.

Egg & Fry Care

Females deposit 20-200 adhesive eggs, usually onto the ceiling of the cavity. The male alone cleans and fans the clutch to maintain oxygen flow; eggs hatch within 4-10 days and the male guards the hatchlings for a further 7-10 days.

Common Challenges

Wikipedia notes there is no scientific evidence that Ancistrus feed on wood; the natural diet is algae, aufwuchs and detritus, so condition the breeders and rear the fry on these foods rather than relying on wood for nutrition.