Auchenipterus nuchalis Care Guide
Auchenipterus nuchalis is a free-swimming South American driftwood catfish active near the surface at dusk and at night.
Compiled by Aquairi from published sources · Published · Updated
Overview
Auchenipterus nuchalis is a South American driftwood catfish of the family Auchenipteridae. Unlike most catfish it is a free-swimming species found near the surface rather than a strict bottom-dweller. FishBase reports a maximum standard length of about 27 cm and notes that males develop thick, ossified maxillary barbels.
Taxonomy
- Family: Auchenipteridae
- Genus: Auchenipterus
- Scientific name: Auchenipterus nuchalis
Habitat
According to FishBase the species ranges across the lower Amazon and Tocantins rivers northward to the Marowijne River, and possibly the Rupununi River in Guyana and the Negro River in Brazil. It inhabits the lower courses of larger rivers, occurs less frequently in flood zones, and appears in large numbers in eroded zones.
Tank requirements
- Minimum tank volume: 200 L
- Temperature: 22-26 °C (72-79 °F)
- pH: 6.0-7.5
- GH: 2-15 °dGH
- Group size: 4 or more individuals
- Lifespan: 8-15 years
- Substrate: soft sand with driftwood and shaded retreats
Diet
The species is an omnivore that leans carnivorous. FishBase assigns it a trophic level near 3.6 and records that it feeds on smaller fish. In aquaria it accepts meaty foods such as frozen and live invertebrates, and over time prepared sinking foods.
Compatibility
This is a peaceful but predatory schooling catfish that occupies the upper and middle water column, becoming most active at dusk and at night. It is best kept in a group and combined with fish too large to be swallowed; very small tankmates may be eaten.
Breeding
FishBase records that the reproductive period occurs during the rainy season. As with other auchenipterids, the modified barbels of the male are associated with internal insemination. Captive breeding is rarely reported and is considered difficult.
Conservation status
IUCN Red List: Least Concern (assessed 12 August 2020).
Auchenipterus nuchalis (Driftwood Catfish) Breeding Guide
Overview
Auchenipterus nuchalis is a driftwood catfish of the family Auchenipteridae, a South American group whose members are active in the upper and middle water column at dusk and night. The most distinctive feature of the family is its reproductive mode: according to Wikipedia, the eggs of auchenipterids are fertilised internally, which is unusual among catfishes.
Sexing
In mature male auchenipterids the anal fin is modified into an intromittent organ used for insemination. A study of the male reproductive apparatus in Auchenipteridae and Callichthyidae (Mazzoldi et al., Journal of Fish Biology, 2007) describes the male of A. nuchalis as having an anal fin modified for insemination, a pair of seminal vesicles, and sperm released as discrete bundles called spermatozeugmata. The modified anal fin therefore distinguishes mature males from females.
Spawning Behaviour & Trigger
Members of Auchenipteridae practise internal insemination: the male transfers sperm bundles to the female, who can store mature unfertilised eggs and stored sperm inside her body for a period. When conditions become favourable, fertilisation is triggered and the eggs are deposited. This decoupling of mating and egg laying is a defining trait of the family and applies to A. nuchalis.
Egg & Fry Care
After the inseminated female deposits her eggs, there is no subsequent parental care reported in the family. The eggs and resulting larvae are left to develop on their own, so any captive rearing would depend on protecting the eggs from the adults and from other tank inhabitants.
Common Challenges
Because fertilisation is internal and egg laying may follow much later, reproduction in aquaria is unpredictable and rarely achieved deliberately. The species is also a nocturnal, schooling open-water swimmer that needs space and dim conditions, making it difficult to observe and trigger spawning. Reliable species-specific spawning protocols are not documented in general aquarium sources.