By popular demand, what sort of fishes the cast of Naruto would keep:
Naruto: Oscars
Sasuke: focus on plants, (Takashi Amano-style) plus large school of glowlight tetras
Sakura: Southeast Asian biotope
Sai: Corydoras sp.
Shino: Farlowella species, breeding
Hinata: Community, primary interest in gouramis
Kiba: Spiny eels
Ino: fancy guppies
Chouji: barbs
Shikamaru: algae and swordtails (the last survivors)
Lee: bettas (breeding)
Tenten: Malawi cichlids
Neji: Discus
Gaara: dwarf cichlids
Temari: Annual killifish
Kankurou: glass catfish
Kakashi: kissing gourami
Jiraiya: Mexican blind cavefish
Orochimaru: fire eels
Tsunade: unusual (shy) tetras
Jiroubou: flag cichlid (Cichlasoma festivum)
Tayuya: firemouth cichlids
Kidoumaru: predatory catfish
Sakon and Ukon: Julies (Julidochromis, Lake Tanganyika)
Kimimaro: ...pufferfish. XD