I have three in a 2.5 gallon.., well planted. They do great on frozen bloodworms, mysis and even cyclopeze... I never feed frog bits, I have heard that can jam their digestive systems... I only feed every other day, and they come running when they see the syringe I use to squirt the food onto their "feeding rock" ..
they have actually dug a little cave under some driftwood I have as a little hidey hole, and do very well... I wouldn't put tetras in with them. Tetras are very good at grabbing food quickly. Frogs take awhile to find it.. They do best in a species only tank.
you can think one frog per gallon if they are alone.. they are said to like a higher ph.. 7.6, but I only ever raise my water to 7 (naturally very soft acidic water). Supposedly they don't need a heater. So far, the tank light has done enough, but I will buy a tiny heater and keep it handy in case of a cold snap the apt heat doesn't handle.
they are very sweet tho once, I was watching one that seemed to have a broken leg. I was very worried, and suddenly it shed its skin and ate it in one gulp. yuk!
lots of plants. Not lots of things that can fall in on them if they dig as they are great diggers. They need a well covered tank (grab that little hole for cords on teh eclipse and tape it shut) and they can't be out of the water. Also don't over feed.
I don't find them particularly messy, but I do 50% water changes weekly, a habit left from my highlight planted tank.
