There are more than 100 different types of fish to catch.

Track your fish by using /fish

Fish caught also have a small chance of being enchanted. Enchanted fish currently have no extra benefits other than being a collector’s item. Enchanted fish are also tracked. If a player has caught the enchanted version of the fish species, a small blue star will appear next to the name in the tracking display.

Here is an incomplete list of where to find each fish:
https://acidmines.fandom.com/wiki/Fish_Species