The Fishes: Ageneiosidae

SILURIFORMES - catfish - Page 3

Family: Ageneiosidae
Family: Cetopsidae
Family: Hypophthalmidae
Family: Trichomycteridae
Family: Callichthyidae

Ageneiosidae
These open water catfish are commonly called slopehead catfish because of their characteristic lateral outline of the head. The skin is naked and only a single pair of short barbels. The family holds three genera, Tetranematichthys, Tympanopleura and Ageneiosus . The latter holds by far the most species. They are open water predators which actively pursue smaller fish.

Media browser - click on picture to select
View from above of a member of the Ageneiosidae	View from above of a member of the Ageneiosidae	Lateral view of a preserved specimen of Ageneiosus showing the characteristically sloped head of the family	Lateral view of Ageneiosus vittatus	An Amazonian boy shows his catch, a slopehead catfish of the genus Ageneiosus

Cetopsidae
This group of open water catfish have a distinctive rounded form to their naked bodies. They are streamlined with small eyes protected by a layer of skin. This family holds four genera, Hemicetopsis, Pseudocetopsis, Cetopsogiton and Cetopsis. These are predatory fish that will attack injured fish and animals much larger than themselves, literally burrowing into the flesh. They frequently damage fish caught in gill nets before they can be removed by the fishermen. They are known to burrow deep into the bodies of dead animals, including man.

Media browser - click on picture to select
Lateral view of a Cetopsis species	Lateral view of a Cetopsis species

Hypophthalmidae
This family, commonly called the lookdown catfish, only holds the genus Hypophthalmus. There are two, possibly three, species in the genus. They are naked skinned, with small eyes set on the underside of the head so that they look downwards and they possess three pairs of barbels. They are pelagic fish which feed on plankton. The gill rakers are long and numerous and developed as a filtering apparatus to collect plankton.

Media browser - click on picture to select
Lateral view of an adult Hypophthalmus edentatus	Lateral view of an adult Hypophthalmus edentatus

Trichomycteridae
This family includes members that live within other fish and will even, in the case of the notorious candiru, enter humans. The fish is said to be attracted by urine so it is advisable in the Amazon to wear swimming trunks and not to urinate in the water. In fact, behave as one would in the swimming baths. Many are small, slender catfish. Most species are free-living and harmless.

Media browser - click on picture to select
Preserved specimen of a Vandellia species. Members of this genus are specialised for a parasitic life and will enter the urethra of mammals	Ventral view of Pseudostegophilus nemurus	Dorsal view of Pseudostegophilus nemurus
The anterior half of a Trichomyctid parasitic catfish caught in a forest stream	Ventral surface of a Trichomyctid parasitic catfish caught in a forest stream	Dorsal surface of a Trichomyctid parasitic catfish caught in a forest stream

Callichthyidae
This is a large family of small armoured catfish that are often highly abundant and found in large groups. The sides of these fish are protected with two rows of scutes and there are usually two pairs of barbels and a pair of filaments or fleshy flaps. They are predators on small insects and other invertebrates.

Media browser - click on picture to select
Lateral view of Dianema longibarbis showing the rows of lateral scutes. This species is abundant within floodplain lakes and even enters flooded forest	Lateral view of Megalechis thoracata (until recently known as Hoplosternum thoracatum). This species is abundant in floating meadow within floodplain lakes	An unidentified Callichthyid catfish - probably C. callichthys	Lateral view of Callichthys callichthys, a common floodplain species