I know I looked for LEDs awhile ago but can't remember which ones I found. Right now i jut use a 6 in fluorescent green light from optronics. They sell at Sportsmans. I bought a two foot one from their same brand used it once and leaked water and blew bulb. I have had the 6 incher for like 3 years with no problem.
With LEDs and buoyancy issues. I plan in using 2 in ID clear pipe with a 1 in white PVC with LEDs lights attached to it. Then slip that inside clear tube and presto. Now for weight.Ill just add some lead weights or straight lead to it to make sink.