Legendary Fish

Angler
Use any fishing rod and fish off the pier into the ocean between 10 p.m. and 8 a.m. If you do not get one the first time, try again the next day.

Catfish
Fish with any fishing rod in the pond which is in the secret underground cavern in Winter. If you do not get one the first time, try again the next day.

Char
Fish with the fishing pole in the waterfall or in any river or the sea after you have cooked up the dish of Sashimi, Sushi, and Grilled fish. If you do not get one the first time, try again the next day.

Sea Bream
Sell 200 or more fish, then fish with the fishing pole in any season except for Winter. If you do not get one the first time, try again the next day.

Squid
Get the fishing pole and throw a small fish off the pier into the ocean in Summer. If you do not get one the first time, try again the next day.