They may carry some parasites that can infect fish and other species, including humans. My snails were all doing fine, I had recently found a great solution to a minor mite problem I had, so the snails were completely mite-free. Those may interest you: What to do with a clutch of mystery snail eggs. I seem to have a magnetic like slime or gel that hovers around the snail and at the bottom the tank. 8/26/18 Hello I have 2 mystery snails in a 10 gallon tank by themselves for the last 2 years. ... Tanks with dying inhabitants are a sign of poor water quality, sickly conditions, or even contagious diseases. (2016): “In Korea, this species is known to be a host to the metacercariae Echinostoma cinetorchis, an intestinal trematode parasitic in humans (Chung and Jung 1999). Amber. Mystery snails (or pomacea diffusa) are common freshwater snails to breed and/or keep as pets. Mystery Snail Suddenly Dies. This is normal – it … By setting up your tank with care, adding the snails to the tank properly, and providing general care, you can maintain healthy, happy mystery snails. have been popular aquarium species in the U.S., and ... Diseases From Kipp et al. With snails of any type, the cooler the water, the more they slow down but when the water is warmer, they will become more active. One source is cuttlebone of the type sold for bird cages. One of the main identification features of the mystery snails is their size.