Azumarill is useless without Huge Power. it has no bulk and easily KO'd. It's called a gimmick, and not a good one, since it has so many counters and play around the best you can hope for is a 1 for 1, which in itself is kinda uncompetitive.
Just run normal Azumarill with Huge Power and Choice Band. It is far more reliable and tbh will KO more.