Yes there are also complete aluminium profile led striips in IP68 available.
IP68 water proof is the propper search term for 100% waterproof. It's the last digit code 8.. Lower last number is less waterproof
They are waterproof by beeing casted with Epoxy resin. Problem is, its a solid piece, if it ever burns out the led strip can't be replaced and the complete unit is trash. I've tried one a while ago, they are indeed 100% waterproof and can de dropped in the water. But since they are completely casted and inclosed in epoxy have bad heat dissipation shortening it's lifespan. If the epoxy isn't UV treated it turns yellow after a number of weeks. Filtering light..
There are loads of different aluminium led strip covers available for indoor use. But not all have a snuggly thight fit cover to prevent moist air from getting in. Also outdoor use can be found for extra price are IP65..
The strips in the link above are ideal indoor models, have a snugly thight fitting pvc cover clamped on and the end caps can be siliconed and screwed to the deck. Makes it +/- IP65 Spray waterproof.
Only concern in a closed lid with maybe condensating water accumulting and dripping back into the tank. That is very soft distilled water and relative agressive to aluminium, you don't want that dripping back into the tank. Than put a protective spray coating on the outside of the aluminium profile.
For an open top tank, no issues at all, have used the above strips for many years in several occasions. Still today.
Builded several aqaurium light setups for friends with this.. Yet never recieved one complain all are still happy..