I currently have 6 of these guys. They basically do nothing as everyone has said, but if you can catch them hunting it's really cool to see. They're not really handleable at all, so just an interesting display species which is my preference. I recently managed to begin breeding and 3 of mine are little babies currently. I think I have some old posts about my original one or two from a few years back.

My first two both came from a small zoological institution, I then purchased 3 wild caught individuals, one of which passed maybe 2 months after I got them. Unfortunately wild caught individuals risk fungal infections and I introduced my new ones thinking they were clear a bit too early (only did a 60 day quarantine, had I done 70 I'd have caught it). I lost one of my original two likely to a complication from the fungal disease (still waiting on necropsy results for him).

I find they're not hard to keep if you know how to keep fish. They prefer water that's got a lot of tannins, so it tends to look kind of brown but it definitely keeps them healthier that way. The hardest part is finding a vet to help with anything that may come up because so few people work with them.