Lol!! Olloch should forget about his mid life crisis and remain in his cozy and quaint 10 Gallon cottage.
Alright enough playing . As a male Palma he will not grow much larger than 3" and can actually live quite comfortably for the rest of his life in a smaller 5 gallon tank, so the 10 gallon he is in is actually more than enough room for him to live. He probably would not use all the space or even halfbof the space in a 20 gallon. You also must
consider the stress factor since Pacman Frogs become stressed very easily. e
Especially when they feel overwhelmed by a lot if open space. This makes them feel insecure and exposed. You would probably be better off keeping him in bis 10 gallon and using the 20 for something else.