I really like the 3rd and 4th ones Doug. The 3rd one gives no doubt to its water typing, whereas the 4th one highlights the feminine aspects of the design.
It's a great design, but I have a small suggestion. To try and emphasise its Fighting elements a bit more, maybe try making the bubbles on its hands a bit bigger and rounder, sort of like boxing gloves made from water. Like I said, though, it's an excellent design, and I much prefer it over your scuba diver.
LR.