Tried fishing again for the first time in a long time. Brought a couple stacks (of 25) nightcrawlers and set my Fishing Pole to use Nightcrawlers as bait
Couple casts later, got the message I was out of bait. Thought I had screwed up and hadn't grabbed as many nightcrawlers as I thought. So I went back and got a bunch more and started paying attention
Every time you catch a fish - full stack of 25 nightcrawlers gets removed from inventory
Any time it says that a fish has eaten the bait - a full stack of 25 nightcrawlers is gone