Oxydoras niger, the ripsaw catfish or cuiu cuiu, is a species of thorny catfish native to the Amazon, Essequibo and São Francisco basins in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru and Venezuela.

It feeds by shifting through sand and detecting eatable parts with the taste receptors in the roof and floor of its mouth.

Behavior may vary with age as older individuals in captivity have been seen roaming their cages regardless of light or cover.

It is difficult to pinpoint the exact reasons behind their behavior because of the lack of evidence, more studies would need to be conducted to be conclusive.

This migration is thought to allow their species to disperse over large areas and increase survival.

[8] Although natural disasters are not the only thing they need to worry about, this run is in danger from the increasing number of dams in the Amazon.

Overall, Ripsaw Catfish have an inefficient and slow reproductive cycle that has hindered their species' success in increasing their population.

[10] This process is not specific to catfish and is often displayed in insects, it is where animals will grind two bony or hard structures together to produce noise.

Their mouths are inferior, meaning they are downward facing, allowing them to suck food off the bottom of rivers and eat various organisms.

[12] There are key differences among other fish within their genus, which include having a body width at the clavicles that is smaller than their head length.

In previous studies, larger swim bladders have been associated with a higher sensitivity to high frequencies, yet within thorny catfish, this was the opposite.

These fish possess very durable bodies, except they are sadly coded red on the endangered species list and this can be attributed to several factors.

It also takes them a long time to reach sexual maturity and this in turn means they reproduce slowly.

Not being able to increase their population quickly from slow reproduction is detrimental for them as it is crucial to reproduce for species to survive.

Due to the Amazon being such a diverse ecosystem, parasites are very prevalent there within fish communities and often thrive.

A study was conducted in the basin of Solimões River in Brazil to find out how many ripsaw catfish were infected with parasites.

Of the fish chosen for this study, 18.5% possessed intestinal infections composed of Paracavisona impudica, 3.7% by Cucullanus grandistomis, 14.8% by Dadaytrema, and 3% by Proteocephalus kuyukuyu .

There was a very diverse range of parasites among the Oxydoras niger, with monogeneans being the most prevalent, with acanthocephalans and digeneans after.