Fallounder turns into rot when it dies in your inventory

Just had three Fallounders in my inventory, instead of killing them right away to get leafy meat I waited until they spoiled so the meat would be fresher. Instead of meat I got three rot in my inventory upon their death. This is inconsistent with how other fish spoils - other ones turn into their respective food items (fish meat/fish morsel/popcorn/corn). 

Not sure if Bloomfin Tuna (which also turns into leafy meat when killed) executes the same behavior but might as well check them too.