Stumbled across this on Martha and just had to try it!
The gelatin recipe is interesting; you add your own food colouring so you can make the colour more subtle. Isn't it pretty? And the sweetness is toned down quite a bit too, which I like lot.
Once the gelatin is set, make slits with a warm, sharp knife and slip the little fishies in.
This little red guy is taking the plunge.