Ripsaw catfish (Oxydoras niger) care guide
- Group
- Freshwater fish
- Other names
- Ripsaw cat
- Family
- Doradidae (thorny catfishes)
- Origin
- South America: Amazon, São Francisco and Essequibo river basins, possibly the Orinoco. Lives over muddy beds in rivers and lakes, often in groups.
- Water
- freshwater
- Maximum size
- 100 cm
- Temperature
- 21–26°C
- pH
- 6–7.8
- Hardness
- Up to about 25 dGH
- Minimum tank
- 5000 litres
- Care level
- expert
- Temperament
- peaceful
Care
A huge, peaceful doradid with a dark grey body and a row of sharp, thorn-like plates along each side, which gives it the name ripsaw. FishBase gives a maximum of 100 cm standard length (commonly about 59 cm) and a weight of up to 11 kg, so a cute juvenile soon becomes a very large fish. It is only for public aquariums or keepers with very large indoor tanks or ponds. No source gives a tank size; around 5,000 litres for an adult is our rough estimate. Use a soft sand floor, a few large pieces of wood or caves, very powerful filtration and big, frequent water changes. Net and handle it with great care: the side thorns and fin spines catch in nets and can cause painful cuts, so move large fish in a container rather than a net. FishBase gives a pH range of about 6.0–7.8 and hardness up to 25 dGH, and quotes temperatures from the low to mid 20s °C (with a wider range tolerated); our 21–26 °C range combines these. FishBase lists it as Least Concern on the IUCN Red List (2020). It forms schools and makes seasonal migrations in the wild, and is fished for food in parts of its range. We could not find its PlanetCatfish page when checking, so this page uses FishBase. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: FishBase (fishbase.se/summary/Oxydoras-niger.html). Checked October 2026.
Diet
In the wild it sifts mud for detritus, insect larvae (such as midge and mayfly larvae) and small crustaceans. In captivity offer large sinking pellets and tablets, plus frozen foods such as bloodworm, mussel and prawn. Feed generously but avoid overfeeding, as adults are very large.
Compatibility and tank mates
Peaceful towards fish it cannot swallow, so it suits very large systems with other big, calm fish such as large doradids, pimelodids, big characins and large peaceful cichlids. Small fish may be eaten by adults.
Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.