When there is no specific city, county, state or federal prohibitions for the fish or animals, you can legally possess the fish or animals.
A person is guilty of unlawful transportation of fish or wildlife if he/she knowingly imports, moves within the state, or exports fish, shellfish, or wildlife in violation of any rule of the Fish and Wildlife Commission or the WDFW Director governing the transportation or movement of fish, shellfish, or wildlife, and the transportation involves big game, endangered or protected fish or wildlife, deleterious exotic wildlife, or fish, shellfish, or wildlife having a value greater than $250 (RCW 77.15.290 (2)(a)).
A person is guilty of unlawfully releasing, planting, or placing fish, shellfish, or wildlife if the person knowingly releases plants or places live fish, shellfish, wildlife, or aquatic plants within the state (RCW 77.15.250, WAC 232-12-271).
A person is guilty of unlawful release of deleterious exotic wildlife if the person knowingly releases, plants, or places live fish, shellfish, aquatic plants, or wildlife within the state, and such fish, shellfish, or wildlife has been classified as deleterious exotic wildlife by rule of the Fish and Wildlife Commission (RCW 77.15.250, WAC 232-12-017).
It is against the law to transport live fish or live wildlife without a permit to do so from WDFW.