I designed this for cutting on my X-Carve CNC, but it'll 3d print just as well.
I used an ocean shader in Maya to create the water effect. The hole should fit any standard votive candle. I'd recommend an LED: Hot candles & filament don't mix too well.
I'd use at least 20% infill, or you'll have a problem catching the troughs of the waves with some form of support.