Endwalker Fisher Studium Delivery: can't turn in Giant Aetherlouse

[Nezerius]

I just now attempted to get the collectible, but I caught 6 non-collectible instead. I didn't realize I was supposed to get collectible until I tried to turn them in. So now I wonder where to get them from.

Collectable fish are from the same fishing spot, but require the "Collect" action to be enabled.