It looks like a regular hitch hiking snail took hold on one of my trumpet snails. No, let me rephrase that...I actually saw the one snail lift the trumpet snail up...and I would like to know if he is killing it, breeding with it, eating it, what?!!!
OMG! I am such an idiot...I just went back to look and see what was going on, and lo and behold, it's just one HUGE trumpet snail. Sorry. How big do these things get?
I have a couple old guys that are about 1 1/2 inches long. I agree with Sounguru about the shell erosion -- how hard is your water and do you add anything to your water or feed food with minerals and calcium for their shells?