Just follow your fellow divers around, filming their fins. Be in position when the action starts. The best videographers have big fins and slow dive buddies. Your video will be more interesting if it shows divers arriving, rather than a steady diet of tank bottoms and fins. Give Different Looks.
Any viewpoint becomes boring after a while.
You need to vary your shots. Switch views in a natural, storytelling way. For example, viewpoint one is diver approaching sponge, six seconds. And the final view is a wide-view shot of the diver turning from the sponge to swim on. This shows the general location and the unfolding action.