Schistomes, very nasty critters. I remember them from my parasit class. Sometimes it is hard to think that such icky things could be in our fish tanks. Then again, you'd hope that whatever importer is bringing these fish in have taken quarantine precautions. But one can never be sure. And you're right, without a snail host, the parasite dead-ends in the fish.
Don't put soapy hands into your fish tank! Thank you Somonas for clarifying that. I meant to wash your hands completely once you are all done with the work on your tank. When going from tank to tank I used to stick my hands, nets, etc. in a solution of Rid-Ich I used to make up. Probably not the healthiest thing to do, and it really dries out your skin and turns the cuticles blue, but I'd know that it helped get rid of the possible chance of trasnferring fish disease between tanks.
As far as eating around your fish tank, I'm talking don't prepare your food where tank water has splashed all over the counter, or don't go sticking you grubby hands from tank into potato chip bag. Don't go using the same knife you just sliced up fish food with to slice your own meal. And certainly don't leave dead fish lying around, that's just plain gross!
Granted, I am quite guilty of doing that, or forgetting to wash my hands between tank and bites of sandwich. But then again I'm also the type of aquarist who believes that if you won't drink your tank water, then it is not clean enough for your fish. I have had to prove that a few times. Then again, I also once swallowed a live feeder goldfish just to gross out some kids....
Wait, hmmhmm, yup, still got a pulse. I get sicker from eating the Taco Bell around the corner than I do from anything involving my fish tanks, even when I was working on the retail scale.
~~Colesea