Dwarf cichlids
The small, jewel-bright cichlids of South American streams and West African forest brooks — most under 10 cm, fiercely territorial for their size, and a lifetime's hobby inside a single genus.
Lake Malawi mbuna
Malawi's rock-dwelling cichlids — fast, fiercely territorial algae-grazers the lakeshore Tonga named mbuna, "rockfish."
Popular plecos
The suckermouth catfishes the hobby actually keeps — easy-breeding bristlenose, the prized zebra and clown L-plecos, the big royal and common species, and the tireless little otos.
Tanganyikan shell-dwellers
The "shellies" — Lake Tanganyika's smallest cichlids, which spend their entire lives in and around the empty shells of a single freshwater snail.