Fishing

You have the wels catfish in the EU right?

Not in all countries, and it's considered somewhat invasive in Western Europe. But it is the largest native European predator.

I want to eventually catch one IRL

If you actually get the chance, find someone to help you out. They're very hard to find if you don't know where to look for them, and what they've decided to eat at this time of the year this year.

Like you can buy the best bait that absolutely killed it last year around the same time, but they've decided to eat leeches instead of that type of bug this year so they're not interested at all. Or you can kill it with eathworms one week, but the next you don't get a bite because spring floods have stopped, the worms stopped getting washed away, so the catfish start focusing on different prey.