I feed mine as a treat to my fish and have been doing it for over 30 years. Just have to know where they came from and don't get them from somewhere you know there might be something where they feed that might not be good for your fish (chemicals, etc...). Yes, if you feed them often they can get addicted to them, but this is the account for any food fed to fish that they really like. My chocolate and oscar love them, and so does my fire eel and HRP's. Heck even my Tinfoil barbs will eat them and it's quite amusing to watch them running around the tank with them in their mouths and trying to keep them away from the oscar and chocolate. Never have ever had an issue with them in all my years of feeding them every now in then (every other week or so).