I don't really want a water arena at all, but if you insist we could do Pummelo Stadium, which is "Rock Field with a pool of water in the middle."
Although I'd request equilevel instead of equiall then
, so like Equilevel 3 Pummelo Stadium.
Let's put this match idea on hold actually though, thinking about it I'm really busy irl. I'll battle you whenever I free up.