Hello and welcome to Frog Forum!!

Pacman frogs are rather inactive and as a result will rarely need more than a standart 10 gallon tank (maybe 15-20 gallons if you have a huge female).

Babies need to be kept in a much smaller enclosure, 1-2 gallons is perfect. The babies will grow very fast and will reach adult size within a year or two

the key to a successful pacman frog enclosure is security rather than space. The frog must feel safe