A type of plasticized carton for milk, juice and other drinks, originally in the form of a tetrahedron but now primarily in the form of a rectangular cuboid.

Small, colorful freshwater tropical fish.

Colorful freshwater fish, aquarium favorite.

firehead tetra

Tetra Tech, Inc. is an American consulting and engineering services firm based in Pasadena, California.

a Swiss-domiciled multinational corporation of Swedish origin, with headquarters in Pully (Vaud), Switzerland.

The Mexican tetra (Astyanax mexicanus), also known as the blind cave fish, blind cave characin or the blind cave tetra, is a freshwater fish in the Characidae family (tetras and relatives) of the order Characiformes.

The (Phenacogrammus interruptus) a species of fish in the African tetra family, found in the central Congo River Basin in Africa.

The black tetra (Gymnocorymbus ternetzi), also known as the black skirt tetra, petticoat tetra, high-fin black skirt tetra, black widow tetra and blackamoor, is a freshwater fish of the characin family (Characidae).