Usually Tango only rates a 15 minute stay but I've forgotten and left him in there for upwards of an hour. Since it floats in his own tank it's easy to forget I put him in there. :P And then he's PISSED. It's not really a tank, it's just kind of a cup that floats in your tank, like a boat. The reason I like it is that it's clear. Very clear. And Tango really can't see it very well like he can a net, so he comes right up expecting to eat and I scoop him into it. Then I feed him in there, 4-6 pellets depending on how many he got the day before. I took the divider out of mine because I only have one fish with buddies.
I have Hikari sinking carnivore pellets. The corys get one pellet a day broken in half. That way the four of them don't have to wrestle over one pellet. It takes them roughly 15 minutes to them.