Fish
Key
Common - COM – Populations known to occur on SixRivers National Forest
Uncommon - UNC – Individuals found, population on SRNF unknown
| Common Name | Scientific Name | Abundance | Native / Introduced | |
| Lamprey | ||||
| Pacific Lamprey | Lampetra tridentata | COM | Native | |
| Western Brook Lamprey | Lampetra richardsoni | UNC | Native | |
| River Lamprey | Lampetra ayresi | UNC | Native | |
| Sturgeon | ||||
| Green Sturgeon | Acipenser medirostris | COM | Native | |
| White Sturgeon | Acipenser transmontanus | UNC | Native | |
| Shad | ||||
| American Shad | Alosa sapidissima | COM | Introduced | |
| Salmonids | ||||
| Chinook | Oncorhynchus tshawytscha | COM | Native | |
| Coho Salmon | Oncorhynchus kisutch | COM | Native | |
| Sockeye Salmon | Oncorhynchus nerka | UNC | Native | |
| Kokanee Salmon | Oncorhynchus nerka kennerlyi | UNC | Native | |
| Chum Salmon | Oncorhynchus keta | UNC | Native | |
| Steelhead | Oncorhynchus mykiss irideus | COM | Native | |
| Rainbow Trout - nonmigratory | Oncorhynchus mykiss irideus | COM | Native | |
| Coastal Cutthroat Trout | Oncorhynchus clarki clarki | COM | Native | |
| Cutthroat Trout | Oncorhynchus clarki | UNC | Introduced | |
| Brown Trout | Salmo trutta | UNC | Introduced | |
| Brook Trout | Salveinus fontinalis | COM | Introduced | |
| Cyprinids | ||||
| Golden Shiner | Notemigonus crysoleucas | COM | Introduced | |
| Klamath Tui Chub | Gila bicolor bicolor | UNC | Native | |
| Blue (Klamath) Chub | Gila coerulea | UNC | Native | |
| California Roach | Hesperoleucus symmetricus | UNC | Introduced | |
| Speckled Dace | Rhinichthys osculus | COM | Native | |
| Fathead Minnow | Pimephales promelas | COM | Introduced | |
| Suckers | ||||
| Sacramento Sucker | Catostomus occidentalis | UNC | Native | |
| Klamath Small Scale Sucker | Catostomus rimiculus | COM | Native | |
| Klamath Large Scale Sucker | Catostomus snyderi | UNC | Native | |
| Ictalurid | ||||
| Brown Bullhead | Ameiurus nebulosus | COM | Introduced | |
| White Catfish | Ictalurus catus | UNC | Introduced | |
| Stickleback | ||||
| Northern Threespine Stickleback | Gasterosteus aculeatus | COM | Native | |
| Centrarchids | ||||
| Green Sunfish | Lepomis cyanellus | COM | Introduced | |
| Bluegill | Lepomis macrochirus | COM | Introduced | |
| Black Crappie | Pomoxis nigromaculatus | COM | Introduced | |
| White Crappie | Pomoxis annularis | UNC | Introduced | |
| Largemouth Bass | Micropterus salmoides | COM | Introduced | |
| Smallmouth Bass | Micropterus dolomieu | COM | Introduced | |
| Perch | ||||
| Yellow Perch | Perca flavenscens | COM | Introduced | |
| Sculpin | ||||
| Prickly Sculpin | Cottus asper | COM | Native | |
| Reticulate Sculpin | Cottus perplexus | COM | Native | |
| Marbled Sculpin | Cottus klamathensis | COM | Native | |
| Coastrange Sculpin | Cottus aleuticus | COM | Native |