I see the big ones frequently, and I recommend you catch it with a fishing rod. The bigger it is the better the rewards. I got a weapon blueprint once, the piranhas can be decent too sometimes but, salmon are way better. Well, usually they are, it's best to fish for them that to kill them regularly. Hope this helps.
Under appreciated. Super easy to find, and drops PRIME FISH. Prime fish is almost as good as regular prime meat, and WAY better than regular meat. Use a sickle to get tons of prime fish. Super useful for taming carnivores if you don’t have the kibble