SURF. Surf is disputably the best Water move, except for 2-on-2 battles where you might not want an attack that hits both enemies and thus hits neither at full force. It's got more PP, it's got excellent accuracy, and while it's not as strong as Hydro Pump, it's strong enough...especially coming from a Starmie, let alone one with Rain Dance. Plus, it's an HM, not a TM, and pretty much any Water-type and a fair number of non-Water-types can learn it, so it's there for you whenever you need it.Starmie is another problem. Rain Dance powers up only one move; Hydro Pump; Plus, that move is only 5PP, so I kinda need a better water move for longer duration.