As for
Pawn's question about solitary frogs - I bough2 and originally kept them together in a 10g (~30l) tank. They used to play together and were always near eachother.
I moved them both into my 55g and they still play occasionally, but as the tank is so much bigger they probably can't find eachother so easily. On occasion I'll see them chasing and grabbing onto eachother
I like to see them swimming together and jumping around after eachother so I would recomend that you get atleast two. They're only small and contribute only slightly to the bio load of the tank, and they're fun to watch!
