I only have experience with dwarf frogs. Yes they are fully aquatic, but should not be kept in a tank with water deeper than 12, maybe 14, inches or they can get exhausted having to swim too far for air and drown. They are escape artists, so plug any holes in the lid. One of mine got out of the hole the filter and heater wires go though, and I found it under a plastic box at the other side of the room. It lived another six months after jenste on here advised me what to do. Feeding them is the major problem in tanks with fish. Dwarf frogs are almost blind and find their food by smell, and by the time they find it the fish will most likely have already eaten it all. Despite what you may read, they shouldn't be fed on just live (or frozen live) food. Like with most community fish, those are just treats and frogs should be fed on dry food such as HBH frog food (USA) or zoomed frog food (UK), or one of the other makes you might come across.
As crazyforcorydoras said, they should really be kept in species-only tanks.
My dwarf frogs didn't kill my betta, but I had to separate them as they mistook his tail for food and he ended up with finrot. The betta is a dragon scale and is almost blind (a problem with dragon scales is that the scaling can grow over their eyes). Having two types of animal that couldn't see properly was not a good idea. The frogs could smell food, saw a moving shape (the betta) and lunged for it, while the betta couldn't see them coming and move out of the way.