Well are they known to jump out of the tank?
Yes, they can. I'm always surprised when they decide to congregate and I see 6 at once because I'm usually lucky to see one or two. Looking for them doesn't help because they blend in so well. I'm glad yours are doing okay. BTW, I've never had an oto jump in the 3+ years I've been keeping them.Those suckers can hiiiiiiiiiide.