Bio Facts: Catfish, Bristlenose
Paraná River basin, Argentina, South America
Freshwater rivers and floodplains
Body covered in bony plates and a ventral suckermouth; fleshy tentacles found on the head in adult males; females may have tentacles along the snout margin but they are smaller; females lack tentacles on the head; tentacules, tentacles directly associated with odontodes (dermal teeth), develop on the pectoral fin spine of the males of some species. Males also have evertable (capable of being turned inside out) cheek odontodes that are less developed or absent in females. Females also lack odontodes along the snout. Body length: less than 6” (15 cm); coloration is typically mottled brown, grey or black with small white or yellow spots common.
In captivity about 20 years
In the wild they eat algae and aufwuchs (small animals and plants that encrust hard substrates, such as rocks); in the Zoo they are fed a scientifically developed, commercially available fish food and algae and aufwuchs naturally occurring in the exhibit.
Bristlenoses do not school but hide when not feeding; juveniles however are typically found in brightly lit shallows at the water margin making them susceptible to predation by birds.
Breeding takes place in hollows, caves and mud holes in banks. Males may clean the inside of the cavity with their suckermouth before allowing the female to approach and inspect the nest. Courtship includes expanding the dorsal and caudal fins and attempts by the male to escort the female to the nest. While the female inspects the nest, the male keeps close contact. The female may lay 20-200 adhesive eggs, usually to the ceiling of the cavity.
The female plays no role in parental care; the male takes care of its young. Males will clean the eggs and the cavity with its fins and mouth. Males inspect eggs to remove diseased or infertile eggs, and aerate the clutch by fanning them with its pectoral and pelvic fins. During this time, a male usually will not leave the cavity to feed, or will leave only occasionally and quickly return. Eggs hatch in 4–10 days over a period of 2–6 hours; the male guards the eggs for 7–10 days after hatching. The fry remain in the cave, attaching to the walls and ceiling with their mouths, absorbing their yolk sac in 2–4 days and becoming free swimming.
Males of these species are competitive and territorial. Males display to each other by positioning themselves parallel to each other, head to tail, with dorsal and caudal fins erect and cheek odontodes spines everted. If this escalates to combat, the males will circle each other and directly attack the head of their opponent. If an intruding male manages to evict another male from the nest, it may cannibalize the other male’s young.
A male bristlenose may guard several clutches of eggs simultaneously. Females prefer males that are already protecting eggs and may prefer males that are protecting larvae; it has been suggested that the tentacles may act as a fry mimic to attract females, which would allow males without eggs in their nest to compete with males guarding eggs. Several clutches in various states of development from eggs to free-swimming larvae can be found in one nest.
Ancistrus species have the capability of obtaining oxygen through their modified stomach. This allows them to survive in conditions with low oxygen levels.
The name ancistrus derives from the Greek ‘agkistron’ meaning ‘hook’ - a reference to the form of the cheek odontodes. Another common name is ‘jumbie teta’.
These fish are often kept by aquarists as they are dutiful algae-eaters and smaller in adult size than the common plecostomus usually seen in aquariums. They are hardy animals, tolerant to a wide range of water conditions, breeding easily in captivity, and compatible with most other freshwater fish.
The genus Ancistrus includes at least 59 named species. Unnamed Loricarrids are typically identified by an L-number and may continue to be so identified (especially outside academic circles).
Caution should be taken with the spines (odontodes) - although the risk of personal injury is small with this genus the hooked nature of the odontodes means that a bristlenose may become trapped in non-natural material such as sponge filters and netting.
Jacksonville Zoo History:
The bristlenose catfish has been part of the Jacksonville Zoo collection since 2004.