Uaru Uganda nothobranch Ukkarikasago Ukrainian gudgeon U-mark sandperch Umatilla dace Umbrella cichlid Umbrella conger Umpire Triplefin Umpqua dace Umpqua pikeminnow Umpquachub Unarmed dwarf monocle bream Uncinate sculpin Uncombed blenny Undistinguished sabretooth Undulate ray Undulated moray Unicolor coralgoby Unicolor moray Unicolor snake moray Unicorn cod Unicorn crestfish Unicorn grenadier Unicorn icefish Unicorn leatherjacket filefish Unicorn sole Unicornfish Union snook Unipa chromis Unipore snailfish Unknown Unpolished dwarfgoby Unspecked hardyhead Upjaw barb Upland bully Upper Grijalva livebearer Upper Yenisei grayling Upper Zambezi labeo Upper Zambezi squeaker Upper Zambezi yellowfish Upsidedown catfish Upside-down goby Upside-down pipefish Upturned snout rattail Upwelling dwarfgoby Urchin clingfish Uruguay river sprat Uruguay tetra Uruguayan eartheater