A List of British Freshwater Fish on the Wiki.
Family Acipenseridae
Acipenser ruthenus - Sterlet
Family Anguillidae
Anguilla anguilla - Eel
Family Balitoridae
Barbatula barbatula - Stone Loach
Family Centrarchidae
Micropterus salmoides - Large-mouthed Black Bass
Lepomis gibbosus - Pumpkinseed
Family Cobitidae
Cobitis taenia - Spined Loach
Family Cottidae
Cottus gobio - Bullhead
Family Cyprinidae
Barbus barbus - Barbel
Rhodeus amarus - Bitterling
Alburnus alburnus - Bleak
Abramis brama - Bronze Bream
Cyprinus carpio - Common Carp, Ghost Carp
Squalius cephalus - Chub
Carassius carassius - Crucian Carp
Leuciscus leuciscus - Dace
Carassius auratus auratus - Goldfish
Ctenopharyngodon idella - Grass Carp, Mirror Carp
Gobio gobio - Gudgeon
Leuciscus idus - Ide
Phoxinus phoxinus - Minnow
Rutilus rutilus - Roach
Scardinius erythropthalmus - Rudd
Blicca bjoerkna -Silver Bream
Leucaspius delineatus - Sunbleak
Tinca tinca - Tench
Family Esocidae
Esox lucius - Pike
Family Gasterosteidae
Pungitius pungitius - 10 -Spined Stickleback
Gasterosteus aculeatus - Three-spined stickleback
Family Lotidae
Lota lota - Burbot
Family Percidae
Perca fluviatilis - Perch
Gymnocephalus cernuus - Ruffe
Sander lucioperca -Zander
Family Petromyzontidae
Lampetra fluviatilis - River Lamprey
Family Salmonidae
Salmo trutta - Brown Trout
Thymallus thymallus - Grayling
Coregonus pennantii - Gwyniad
Oncorhynchus mykiss - Rainbow Trout
Salmo salar - Salmon
Coregonus vandesius - Vendace
Family Siluridae
Silurus glanis - Wels Catfish