Twig catfish

Class: Actinopterygii
Order: Siluriformes
Family: Loricariidae
Genus and Species: Farlowella spp.
  • catfish has long thin body
  • closeup of catfish head with eggs nearby
  • ghostly catfish with eggs stuck to glass
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Twig catfish

Twig catfish, named due to their resemblance to twigs, are found throughout the Amazon, Orinoco and Panara rivers, as well as rivers of the Guyana Shield. They are one of the only fish known that have evolved to eat wood as a primary energy source.

Size

Twig catfish grow to between 5 and 7 inches (12.7 to 17.8 centimeters) in length.

Native Habitat

Twig catfish have a relatively broad distribution. They are found in the Amazon, Orinoco and Panara rivers as well as coastal rivers of the Guyana Shield. These catfish prefer an environment with a substrate comprised of submerged dead leaves and sticks which helps them stay well camouflaged.

Food/Eating Habits

Twig catfish use dozens of small, uniquely specialized spoon shaped teeth to rasp at wood and algae, their primary source of nutrition. Consuming wood as a primary energy source is extremely rare among vertebrates. Fish in the genus Farlowella are the only known fish evolved to do this.

At the Smithsonian's National Zoo, they are fed a gel diet as well as produce including zucchini and cucumbers. They also enjoy eating all the plants in their exhibit.

Reproduction and Development

An oviparous species, twig catfish lay their eggs in a single layer on vertically situated rocks and vegetation. They do not attempt to hide their eggs in caves or crevices, instead opting to lay them in open water. Males guard fertilized eggs.

Lifespan

Twig catfish are named for their long, thin bodies that resemble a twig or stick. Their noses are pronounced, and their bodies are generally brownish, with two lateral dark stripes running from head to tail. The body is protected by bony plates called "scutes." Thanks to their body shape and coloring, twig catfish can hide easily among sticks, leaves and other vegetation rather convincingly. There is some sexual dimorphism, with females generally having a smaller rostrum and generally rounder in shape when compared to males.

There is no current research being conducted on twig catfish at the Zoo. Their status in the wild is unknown. Catfish in the genus Farlowella are generally considered to be relatively common; however, there is little known about each distinct species.