Catfish
Conservation status
There at least 3,400 different species and between 34 and 44 families of Catfish (new species are still being discovered). This is one of the largest orders of fish. They are freshwater ‘bottom dwellers’ that swim along and close to the bottoms of estuaries, rivers, and lakes. Some species are critically endangered such as the Mekong Giant Catfish (one of the world’s most endangered species), usually found in the Mekong River basin. Conversely the Walking Catfish, found in Florida, is a highly invasive species. The larger species are most vulnerable because of habitat loss, pollution, hunting, and the building of dams. The loss of these would impact local ecosystems. On the other hand, some species have been introduced into new environments where they thrive and upset native food webs and biodiversity. The IUCN cites 191 Endangered Species and 90 Critically Endangered whilst the vast majority (2,071 species) are listed as Least Concern.
Overview
There are Catfish species to be found in all the continents except Antarctica and the Wels Catfish Silurus glanis is indigenous to Europe.
Nearly all Catfish species have whisker-like barbels, which help them to feel and taste, and their bodies are covered with thousands of taste buds. Most are nocturnal, many have excellent hearing, and some have been known to fast. Catfish species can vary in length from 3cm to 5m – from the Pygmy corydoras to the Wels Catfish. Catfish from the Amazon undertake amongst the longest of freshwater migrations - Brachyplatystoma Catfish travel as far as 8,000km when returning to their place of birth.
Most Catfish take in oxygen through their gills. However, the Clariidae family has evolved the ability to swim to the surface to take in air. This is a response to low oxygen levels in polluted water. Another air breathing species – the walking catfish – can survive for 18 hours out of water. Catfish don’t have scales – some are naked (including species who breathe through their skin) and some are covered in bony plates. Catfish can produce all sorts of different sounds and can distinguish between different pitches and locate where sounds come from.
Catfish are commercially important and are fished and farmed for food.
https://www.bbcearth.com/factfiles/animals/fish/catfish
https://en.wikipedia.org/wiki/Catfish