Stonecat

Noturus flavus is the largest of the North American madtom catfishes, inhabiting swift, clean, rocky riffles and shoals across the Great Lakes and Mississippi drainages. It is a nocturnal predator that spends the daylight hours pressed flat beneath large stones or wedged in crevices, emerging at night to hunt aquatic invertebrates, crayfish, and small fish. Its mildly venomous pectoral spines discourage handling — a defence shared by all madtoms.

In the aquarium, Stonecats are fascinating nocturnal inhabitants of river biotope setups. Large, flat rocks that can be raised slightly off the substrate — creating the understone gaps the fish naturally inhabits — are essential furnishings. Lighting should be subdued or timed to allow observation during the fish's naturally active dusk and dawn periods.

They feed on a variety of benthic invertebrates, worms, and crustaceans, and can be trained to accept sinking carnivore pellets delivered at dusk. Their unique ecology, secretive habits, and the opportunity to observe natural sheltering behaviour make them a rewarding specialist aquarium subject.

Water: 12–22 °C, pH 6.5–8.0, moderate hardness; fast current, high oxygen, very clean water. Tank: 200 L minimum; large flat rocks creating understone gaps; minimal fine silt accumulation. Feeding: Live/frozen earthworms, invertebrates, crayfish; sinking pellets offered at dusk. Breeding: Nests under flat rocks; male guards eggs — large stones as spawning sites essential. Compatibility: Semi-aggressive; will consume small fish at night — keep with medium to large robust species.