Sterbai cory

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: sand.

Behavior

Plant interaction: plant safe.

Feeding

Sinking pellets, sinking wafers, frozen bloodworm, and brine shrimp. Sand substrate is mandatory for all corydoras species; sharp gravel damages the barbels. Feed in the evening when corys are most active. Like all corys, sterbai are slow eaters that need food to reach the bottom. In a tank with aggressive midwater feeders, use sinking food that drops quickly. Corys supplement their diet by sifting microorganisms from the sand, which is fascinating to watch but not sufficient on its own.

Compatibility

• Peaceful community fish. Safe with everything that won't eat it.
• The warm-water tolerance makes it the go-to cory for discus, rams, and other species needing 27–30°C.
• Keep in groups of 6+ of the same species. Sterbai corys do not school with other corydoras species.
• Safe with shrimp and snails.
• Avoid aggressive cichlids or large fish that might bully bottom-dwellers.

Origin and habitat

Corydoras sterbai, now reclassified as Hoplisoma sterbai, is a popular armoured catfish endemic to the upper Rio Guapore, also called the Rio Itenez, which forms part of the Bolivia-Brazil border within the Madeira drainage. Knaack described it in 1962, in the same work that named its look-alike Corydoras haraldschultzi; the two are told apart by their head pattern, sterbai having white spots on a dark ground and haraldschultzi the reverse, dark spots on a pale ground. It is named for the German zoologist Gunther Sterba. The Guapore runs soft, clear, often tannin-stained water over old shield rock, and the fish lives in sandy creeks, pools, and flooded forest. Its great selling point is temperature: it is the warm-water cory, comfortable up around 28 to 30 C where most corydoras struggle, which makes it the standard bottom-dweller for discus and other warm-water tanks. The body is dark brown to black with white spots and bright orange pectoral and pelvic fins, and albino and black forms are bred. Like all corydoras it is armoured with bony plates rather than scales, and it reaches about 6.5 to 8 cm including the tail. Nearly all trade fish are farmed.

Breeding

Breeds in the typical corydoras way and is one of the easier corys to spawn. A large, slightly cooler water change is the usual trigger, after conditioning the group on rich foods. Spawning uses the genus T-position, the female holding a few eggs between her pelvic fins while the male fertilises them, then sticking the sticky eggs to glass, leaves, or decor, repeating until she has laid somewhere in the range of fifty to a couple of hundred. Unlike some corys these parents are not reliable egg-eaters, so eggs sometimes survive even in a community tank. They hatch in three to five days, and the fry are easy to raise on crushed dry food and baby brine shrimp.

Common problems

The usual corydoras issues apply. Barbel erosion on sharp gravel is the big one, so a soft sand bottom is needed, and an overfed, fouled substrate breeds the bacteria that infect those barbels, so the sand should be kept clean. New fish often arrive with ich, and being armoured but still medication-sensitive, they should be treated for salt and copper at reduced doses. Occasional dashes to the surface to gulp air are normal for a cory and not a sign of low oxygen unless they are constant. The one thing that sets sterbai apart from most corys is warmth: it wants water on the warm side and does poorly kept cool, the opposite of peppered or panda corys.

Bioload

Further reading

• Stocking ideas by tank size