Care
The Black Cory is an aquarium bred colour strain of Osteogaster schultzei (a species considered by many to be synonymous with O. aeneus).
This black strain was first produced by a German aquarist in the early 90s, and then sent on to fish breeders in the Czech Republic where it has been commercially bred in large numbers ever since. The body colour is typically jet black but the fins are dark brown. Rather confusingly, many suppliers list the fish with the misleading name "Corydoras venezuelanus sp. black". This line bred black strain of O. schultzei has no Venezuelan origins and is not a variant of O. venezuelanus (which itself is another "aeneus type"). Misunderstanding is likely to have arisen due to the occurrence of a black wild form of O. venezuelanus - but this is not the same fish. The wild black form of O. venezuelanus has not been exported for the aquarium trade in any great numbers. If in any doubt, juvenile black C. schultzei display reddish fins which darken as they mature. The black form of O. venezuelanus, however, sport a reddish adipose and dorsal fin, but the anal, pelvic, and caudal fins are grey. This peaceful species is ideal for the mature community aquarium, and should be maintained in groups of 5 or more due to shoaling nature. Unfortunately, it can be a little prone to barbel infections/erosion, so it is of paramount importance that the fish are kept on a soft sand substrate (rather than gravel where waste can build up unseen) in order to protect these delicate sensory organs. Regular maintenance, including frequent partial water changes, should be carried out in order to keep these fish in good condition. Provide plenty of shady areas amongst driftwood, rocks, and areas of dense planting. Other peaceful species such as some of the smaller pencilfish, tetra, and rasboras make ideal tankmates, and their presence as "dither fish" in midwater will encourage the Corydoras out into view more often. Corydoras have the ability to breathe air intestinally, so a small gap should be left between the surface of the water and the cover slides in order for the fish to come up to the surface and take air in. It may do this numerous times per day.
Young Black corys seem to require a lot of protein to produce their dark pigmentation and must be fed generously whilst growing.
Osteogaster was recently split from Corydoras and contains the Bronze cory group.
Feeding
Sinking catfish pellets, frozen foods such as bloodworm, white mosquito larvae and vitamin-enriched brineshrimp.
Breeding
This species has been bred in the home aquarium. Mature pairs can be triggered into spawning by performing a large, slightly cooler water change. The pair will adopt the classic "T position" where the male fertilises the eggs that are held between the female's pelvic fins. The adhesive eggs will then be deposited onto plants, decor, or the sides of the aquarium etc and the process repeated. Unfortunately the eggs of this species are prone to fungus, so some fishkeepers like to add a small amount of methylene blue to the breeding tank. The eggs generally take 3-4 days to hatch after which time the tiny fry should be offered finely powdered first foods. A few days later they will be able to take newly hatched brineshrimp.
