You can also use whole fishes. Use the () tag.
Here's my "Angler's soup" example. Often you get some small fish with the fishing rod, but not enough for the original fish soup recipe. This recipe needs only one tiny fish, the second is optional
Be careful though, if the fish does not fit in the pot the extra disappears, so do not try cooking 15kg salmons with this recipe.
.TinyFIshes. *COOKERY* /10/ \20\ %20% :148
{Raw fish} (1) [remove] [boil]
{Raw fish} (1) [remove] [boil] [optional] '+ More up to 4lbs total'
{Water} #2# [remove] [boil]