Orinoco dolphin catfish

Care at a glance

Overview

The Orinoco dolphin catfish is a smooth, blunt-headed open-water swimmer shaped like a small gray porpoise, best kept singly. It cruises the middle of the tank almost constantly and takes its food on the move, coming into its own after dark. It is mostly peaceful with larger fish but is a real predator that will eat any tankmate it can swallow, so keep companions well above mouth size and choose them with care. Feed meaty foods, earthworm, prawn, and strips of fish, along with sinking pellets. It needs a long tank of around 400 liters or more for room to swim.

In the wild

Ageneiosus magoi lives in open water across the Orinoco llanos of Venezuela, cruising slow rivers and floodplains over sand and mud and hunting on the move. Give it a large, open tank with long clear swimming lanes, a soft substrate, moderate flow, and some cover at the sides. Keep the water warm and soft to neutral at 23–28 C and around pH 6.0–7.5, and dim the lighting so it feels secure.

Good to know

Ageneiosus magoi is a compact driftwood catfish, family Auchenipteridae, reaching about 18 centimeters. It is an open-water hunter rather than a bottom hugger, and it fertilizes internally. Breeding is not recorded in aquaria, but in the genus the process is unusual: males develop a modified anal fin and heavily reworked maxillary barbels used to grip the female.

Did you know

When they come into breeding condition, male Ageneiosus rebuild their maxillary barbels into stiff, bony, tooth-edged hooks, almost like small harpoons, and use them with a modified fin to clasp the female during internal mating. Outside the season the barbels turn ordinary again.

Common questions

Related species

• Bottlenose catfish

  Ageneiosus marmoratus

  Freshwater

  7.9 in (20 cm)95 gal (360 L)72–79°F (22–26°C)
• Dwarf dolphin catfish

  Tympanopleura atronasus

  Freshwater

  5.9 in (15 cm)70 gal (265 L)73–82°F (23–28°C)

• 

  Horseshoe catfish

  Tetranematichthys wallacei

  Freshwater

  8.3 in (21 cm)79 gal (300 L)73–82°F (23–28°C)

• 

  Common woodcat

  Trachelyopterus galeatus

  Freshwater

  8.7 in (22 cm)50 gal (190 L)72–82°F (22–28°C)

• 

  Striped woodcat

  Trachelyopterichthys taeniatus

  Freshwater

  5.9 in (15 cm)53 gal (200 L)73–82°F (23–28°C)

• 

  Jaguar catfish

  Liosomadoras oncinus

  Freshwater

  9.1 in (23 cm)65 gal (245 L)72–82°F (22–28°C)