Thayeria boehlkei is a species of characin fish endemic to the Amazon river basin and Araguaia river, in Peru and Brazil respectively. The species is popular with aquarium hobbyists where it is traded under a variety of common names including blackline penguinfish, blackline thayeria, hockey-stick tetra, penguin fish and penguin tetra.
The fish is named in honor of James E. Böhlke (1930-1982) of the Academy of Natural Sciences of Philadelphia, because of his interest in and contributions to the knowledge of South American characids.
Thayeria inhabits small streams and the margins of smaller rivers in the lowland Amazon basin, where it is part of the highly diverse Neotropical fish fauna.
The species feeds on worms, small insects, flake food and crustaceans.
In captivity, this normally schooling species forms pairs that scatter their many adhesive eggs amongst plants. Clutch size is very large and may be up to 1000 eggs, the embryos of which are black in colour The eggs hatch in about 20 hours and are free-swimming after 4 days.
The species is best kept in groups, to allow the species to school, in tropical freshwater community aquaria with other peaceful, non-predatory fishes. This fish tolerates a fairly broad range of water pHs, but prefers acidic water for breeding.
