This section is written for aquarium hobbyists, professional aquarists, and academic researchers who need to maintain experimental fish in the lab. It is presumed that the reader knows the basics of aquarium care and maintenance (e.g., biological filtration). For some species, captive and breeding requirements are unknown or can only be guessed at. For other species, captive propagation is impossible (or impracticable) without resorting to hormone injections and artificial insemination techniques usually outside the realm of the average aquarist. Although the care and husbandry requirements of state- and federally-protected fishes are discussed, readers are urged to know and follow applicable state, provincial and federal regulations restricting or prohibiting the possession of protected species.