Well like I mentioned before it's great you recovered your pixie converting to an all aquatic setup for her. To be considered though, pixies are mostly found in pools of water (semi-aquatic), whereas pacmans are typically found in the forest floor scattered among leaf litter or what have you. Generally from what I've seen - even though I don't own a pacman (yet) - is their ability to swim is incomparable to a bullfrog. Bullfrogs built with long webbed feet and body structure to stay a float with their nostrils and eyes staying above water. Also they can stay submerged for a considerable amount of time as I'm sure you are already aware of when you switched to an aquatic setup.

When you take a pacmans' physique compared to a bullfrog, then you see why bullfrogs do so well in aquatic setups. Look at the American cousin subset species, their pretty much only aquatic for the moist part on logs among pond banks, etc. I myself, have considered an aquatic setup for my pixie because I really want him to swim more since he's always found in his water bowl. If I had to choose though what would be best for your pacman, it would definitely be terrestrial land how they typically would be found in the wild (South America).