They caught a lot of ____ yesterday.
when the fish are caught in the same lake, river, etc. we don't use fishes.
But ''fishes'' can be used when they are caught in different water such as Lake A, Lake B, riverA, or river B
When fish are caught in the same lake , river etc the word fishes can be used,although it is not a common use. It has nothing to do where the fish were caught , as a fisherman could have caught numerous fishes anywhere . The plural of fish is fishes but it is rarely used in any context.