Why would they use a LED? You can get laser diodes, which look exactly like LEDs but emit focused beams. Are you sure they aren't laser diodes? Selling LEDs as lasers is more of a case for false advertising than the other claims.
I saw these in various pet stores and wonder if you could accidentally blind a fish if it swam in such a way that the beam crossed it's eye.
Other than that, this seems like a variation of UV sterilization, at least, that's what the claims make it sound like.