Here is a thought. I bought an LED light at a local store for less then $2 and Walmart has them cheap also. Mine is about a foot long. Possible you could double condom it with a small rock at the bottom to keep it floating upright. I may try that myself. I read that Navy Seals double condom ordinary cameras for underwater picture taking.
The problem was finding some that wasn't lubricated or talcum that didn�t mess up the lens.
