My first thought, too. I'm even more skeptical when I see the guy making the following claim:
They're also native critters, found commonly in Florida waters and throughout the world, which should eliminate concerns of some new bug running amok in the environment, he said.
Given that their mosquito-larvae food is obviously so plentiful worldwide, why is it that these little critters don't do a better job of controlling mosquitoes already? Could it be that they eat other things, too? (Maybe beneficial things?)
I don't know that I'd be too quick to rely on this little scheme. Something tells me there's much less than meets the eye here, except perhaps the potential for unintended harm.