Alright, a 1 on 1.
Banned moves: toxic, substitute and direct healing (including rest)
Arena: flooded basement.
A flooded basement where the water is around knee high, some cardboard boxes are wet and floating around. Also several items that are lying on racks that can be used if wanted.
Pokémon limitations: only water pokémon that can fit in a basement. No chinchou/lotad line. They have an unfair advantage with their electric or grass subtype.
First attacker will be decided at random because of the limited selection in pokémon.
I'll send out Kaiza, my male shellder.