I know it's not "necessary" but try to give it enough room in the water to swim around in. My two EWD (one of whom has been rehomed as he was being attacked by my turtle and I didn't have enough room to give him a decent size tank of his own) both like to swim, even the one who's missing half his tail and one leg(I got him that way). Stompy has about 1.5 square feet of water, just deep enough for him to submerge in. He loves swimming, but he's not very good at it because he's missing vital swimming parts, so I can't have the water too deep. When I had him, Not Stompy had a full 4foot tank worth of water (shared with the turtle) and he used every inch of it.
