In my 10 gallon aquarium there are three Neon Tetras and one Dwarf Gurami. Over previous days I have noticed one Neon Tetra had a lump the size of a little snail shell in his stomach. This morning I notice another Tetra with two lumps in his stomach, larger than the other neon tetra's lump. I believe that there is a parasite doing something to their brains since a similar thing happened to my guppy, and she died a week ago after getting snails stuck in her digestive track. The water is doing fine, there are plants in the aquarium, the aquarium has a filter and I don't know what this is! Please help, I fear that the other fish may get this weird brain thing and get them killed to.