Well, the problem is that the agreement was made so that we'd have to get permission to add anything, and Kahvi (still!) hasn't gotten around to that last I checked. He said he was going to meet Holykiwi soon and that he would do it then. However until he does so all we can do is fix bugs and try to recreate Ighalli's god system. Neither of which anyone seems to have taken up.
Swimming and drowning exists. Dolphins and frogs can swim, and I think rats can too. Anything that can't swim, if it happens to fall into water, drowns.