Probably because of where I'm from, my first thought was "that's a reeeeeally niche app" because around here 'noodling' has a different meaning: https://en.wikipedia.org/wiki/Noodling
This is new to me!
You probably figured it out from context, but “noodling” here is to play around with ideas, to mull them over, ponder, brain-storm.
A phrase in my part of the US is “Let me noodle on that”.
We use 'noodle' for thinking here, too. It's just more fun to think of a catfish finding app.