A few fish farms
Fish farms are a source of food in Black & White.
Unlike fields, they can't be built: only found naturally in bodies of water, be it lake or coast. Fish farms will regenerate over time, even if fully harvested, making them a viable food source over the long run.
They can be harvested by a player, a creature (if it learned how to fish by watching villagers), villagers, or fisheman disciples. They normally provide more food than fields, up to about 1500. There are places where villagers or the creature can fish, but the player cannot, such as the inlet near the Aztec village on Land 1.
Fish will increase your creature's fatness more than grain, but less so than meat.
Oddly, the texture for the fish when picked up is similar to that of grain.