This video says about itself:
South American Catfishes – Hoplosternum littorale, Platydoras armatulus & Corydoras sterbai.
(Dec. 10, 2009) — Name all the venomous animals you can think of and you probably come up with snakes, spiders, bees, wasps and perhaps poisonous frogs. But catfish?
A new study by University of Michigan graduate student Jeremy Wright finds that at least 1,250 and possibly more than 1,600 species of catfish may be venomous — far more than previously believed. The research is described in a paper published online Dec. 4 in the open access journal BMC Evolutionary Biology.
The terms venomous and poisonous are often used interchangeably, but incorrectly. There is, in fact, a difference between a venomous insect and a poisonous insect: here.
In the animal kingdom, it pays to look more dangerous and less tasty. It also helps if harmful species resemble one another so that predators might “learn” more easily to avoid both. A new example of this form of mimicry has been discovered among catfish that live in the Amazonian basin, where a school of spiny, armored catfish (from the subfamily Corydoradinae) might contain three distinct species. The findings were described online January 5 in Nature: here.
Capable of growing to 120cm/4′ or more, Phractocephalus hemioliopterus, as it is known to science, hails from the Amazon River in South America. They are popular aquarium fish despite their size making them totally unsuitable for most home aquaria: here.