That's a fair point with introducing any new species into the tank. What did you end up doing to eradicate them and do you have plants in your tank?Make sure you really want assassins. I tried them in a shrimp tank. They promptly ate the snails then I would see them attacking adult shrimp, and baby bushynose plecos. I had a terrible time getting rid of them, and they just kept reproducing. They definitely destroyed the ramshorns though.
Could go either way. I've had them ignore plants and eat them like salad. May not be worth the risk if you value your plants.wont the leos destroy my plants?