You won't get reflections at all if the camera is underwater. You will however be buying a new camera. Your choice.
I believe this is the best option
BUT If you still feel you really need to take nice pictures without reflections: you can build a small glass cube to insert small webcam in it and let is sink.
im sure everybody has an old webcam that you do not use
and 4 pcs of small square glass with some silicone requires no budget.