I have foud a very strange looking creature stuck to the side of my tank. at first i thought it wass a coiled up worm but then i noticed it had to tenticles. and the coiled up bit appears to be a shell. it kinda looks like a brine shrimp. i fed my fish a couple of bags last month. could it be that one surived!!!!!!!! the onluy other option is it that it is a snail. but i havent introduced any plants or fish for a good few months. could it be that i have my own livig organisam evolving in my tank