January Tetra

About

The Costello Tetra (Hemigrammus hyanuary) is a small, slender characin from the Amazon River basin that turns up in the hobby far less often than it once did, which is a shame because it's a genuinely attractive and easy-going little fish. It closely resembles the head and tail light tetra but has a more elongated body, and the two are occasionally mixed up in the trade. Like most members of its genus, its taxonomic placement is currently listed as uncertain, and the broad Hemigrammus grouping will likely be reorganized as taxonomists work through the 70-plus species crammed into it. In the aquarium, this species is thoroughly peaceful and not a fish that holds its own against rowdy or much larger tankmates. It does best alongside other gentle South Americans. Think pencilfish, Corydoras, Apistogramma dwarf cichlids, and similar-sized tetras. Keeping it in a group is non-negotiable: a minimum of six works, but ten or more really lets the shoaling behavior come through properly, and the fish look far better for it. Breeding is possible for dedicated keepers willing to set up a separate spawning tank with soft, acidic water and dim lighting, as the eggs and early fry are sensitive to light. A forgiving choice for anyone comfortable with the basic needs of small South American tetras.