Arter
- Vieja bifasciata Cichlider, Central Amerika
- Vieja breidohri Cichlider, Central Amerika
- Vieja fenestrata Cichlider, Central Amerika
- Vieja guttulata Cichlider, Central Amerika
- Vieja hartwegi Cichlider, Central Amerika
- Vieja heterospila Cichlider, Central Amerika
- Vieja maculicauda Cichlider, Central Amerika
- Vieja melanura Cichlider, Central Amerika
- Vieja synspila Cichlider, Central Amerika
- Wajpamheros nourissati Cichlider, Central Amerika
- Wallaceochromis humilis Cichlider, Øvrige Afrika
- Wallaceochromis rubrolabiatus Cichlider, Øvrige Afrika
- Wallaceochromis signatus Cichlider, Øvrige Afrika
- Xanthichthys auromarginatus Saltvand, Fisk - Aftrækkere
- Xanthichtys mento Saltvand, Fisk - Aftrækkere
- Xanthichtys ringens Saltvand, Fisk - Aftrækkere
- Xenia Saltvand, Koraller - Blødkoraller
- Xenochromis hecqui Cichlider, Tanganyika - Fritsvømmer
- Xenomystus nigri Ferskvand, Diverse
- Xenopus laevis Ferskvand, Padder
- Xenotilapia bathyphila Cichlider, Tanganyika - Sandcichlider
- Xenotilapia boulengeri Cichlider, Tanganyika - Sandcichlider
- Xenotilapia burtoni Cichlider, Tanganyika - Sandcichlider
- Xenotilapia caudafasciata Cichlider, Tanganyika - Sandcichlider
- Xenotilapia flavipinnis Cichlider, Tanganyika - Sandcichlider
- Xenotilapia leptura Cichlider, Tanganyika - Sandcichlider
- Xenotilapia longispinnis Cichlider, Tanganyika - Sandcichlider
- Xenotilapia melanogenys Cichlider, Tanganyika - Sandcichlider
- Xenotilapia nasus Cichlider, Tanganyika - Sandcichlider
- Xenotilapia nigrolabiata Cichlider, Tanganyika - Sandcichlider
- Xenotilapia ochrogenys Cichlider, Tanganyika - Sandcichlider
- Xenotilapia ornatipinnis Cichlider, Tanganyika - Sandcichlider
- Xenotilapia papilio Cichlider, Tanganyika - Sandcichlider
- Xenotilapia rotundiventralis Cichlider, Tanganyika - Sandcichlider
- Xenotilapia sp. "fluorescent green" Cichlider, Tanganyika - Sandcichlider
- Xenotilapia sp. "katete" Cichlider, Tanganyika - Sandcichlider
- Xenotilapia sp. "kilesa" Cichlider, Tanganyika - Sandcichlider
- Xenotilapia sp. "ochrogenys ndole" Cichlider, Tanganyika - Sandcichlider
- Xenotilapia sp. "papilio sunflower" Cichlider, Tanganyika - Sandcichlider
- Xenotilapia sp. "red princess" Cichlider, Tanganyika - Sandcichlider