We have had Zipper the zebra nerite snail for 5 weeks. Our 5gal tank was set up in March and is cycled. Betta and 3 shrimp have been in the tank since late March/April. Zipper is, from what I can tell, a healthy snail. He (we will just assume "he" for now, as I've seen no eggs) had all appendages when we purchased him. He has spent the better part of 5 weeks under a rock, literally. Every now and then he will come out at night and cruise the glass, but the poor kids almost never get to see him because he only comes out after bedtime, spends a couple hours out, and by daybreak he's hidden again. This week I hadn't seen him much at all, but this evening he came out before the tank lights even turned off. The kids got to watch his mouth move as he cleaned the walls. I noticed one of his antennas was VERY short, perhaps only 1/6 of it's original super long length. The other was about 2/3 of its original length and bent. While we were watching him, the betta came by. I didn't notice him touch the snail, but I thought the kids bumped the tank because the snail shrunk down into his shell (on the glass). A few minutes later he got to moving again and the betta came right up and chomped off the rest of the 2/3 antenna. Now both antennas are the same, about 1/6 the original length. What does he use these antennas for, and will he be ok without them? Any suggestions for what to do next, if anything?