Select options Peru Sailfin Tetra (Crenuchus spilurus) (Copy) $7.49 A beautiful tetra originating in the acidic blackwaters of the Amazon and Orinoco basins, the Sailfin Tetra is a medium-sized species that makes for an impressive display fish as an adult. Both sexes have the namesake large dorsal fin, but mature males will have an extremely elongated, brightly colored fin. In the wild, they tend to be found in small groups in shallow waters, usually in areas with substantial cover in the form of leaf litter, fallen branches, or other vegetation. In the aquarium, they can be shy at first but will quickly become more bold if given plenty of cover. A great and showy fish for densely planted or hardscape tanks.