I was looking at my mystery snail and noticed that his antennae look shorter then they did when I bought him a week or two ago. Is this suppose to happen or did maybe one of my fish bite them off? He is in a 48 gallon with 1 hi-fin platy, 4 Black long-finned skirt tetras, 1 gold killifish, 1 Florida flagfish, 4 Cherry Barbs, 1 Farlowella, and 2 Dojo loaches. Also, will his antennae grow back?