Bristlenose Pleco

Scientific name: Ancistrus cf. cirrhosus

Adult size: 8–15 cm, commonly 12.5 cm

Origin: captive-bred; wild relatives from South America

Water: 21–26 °C, pH 5.5–7.5, 1–15 dGH

Group: one, or a pair; territorial with its own kind

Diet: mostly vegetable matter, algae, wood

Temperament: peaceful with other fish

The bristlenose is a suckermouth catfish that grazes algae and stays a manageable size, usually 8–15 cm, with Seriously Fish giving 12.5 cm for the common form, rather than the 40 cm or more of a common pleco, which is the usual mistake. Virtually all fish in the hobby are captive-bred Ancistrus cf. cirrhosus of uncertain wild origin; the wild A. cirrhosus comes from the Paraná basin in South America. Mature males grow the fleshy tentacles on the snout that give the fish its name, while females have at most a little stubble. It is a mostly nocturnal, peaceful fish with other species but territorial with its own kind and with similar-shaped catfish. Practical Fishkeeping puts its diet at 90–95 per cent vegetable matter, with algae, aufwuchs (the film of algae and micro-organisms on surfaces) and wood all on the menu, so a piece of driftwood is part of the diet rather than just decor. Males guard eggs and fry in a cave.

Water: 21–26 °C and pH 5.5–7.5, hardness 1–15 dGH. It produces a lot of waste for its size, so use good filtration and keep up regular partial water changes.

Tank and planting: a tank of at least 60 × 30 cm for a single fish or pair, with driftwood to rasp on, a cave or two and shaded spots. Larger quarters are needed for a group.

Feeding: algae wafers, spirulina tablets and blanched vegetables such as courgette, spinach or cucumber as the staple, with occasional frozen daphnia or bloodworm. Remove uneaten vegetables after a day.