I've got several (and threw all but one back) - various and no bait (my Sim does have full fishing skill and has completed the fishing aspiration). Also got a 'good' quality royal sabrefish from meeting dolphins in the cave rabbithole. It's just luck - it took me forever to get the leopard shark to complete my fish collection - I tried every kind of bait, fishing from a fishing sign, fishing in deep water, fishing near corals. Last night, I got two or three fishing with no bait. (I was actually trying to get the final item for the Sulani treasures collection. Instead, I got every single endangered and rare fish.)
