Went to Walmart & came home with sick snails and a sick pleco

I went to Walmart yesterday. I couldn't help but buy 3 apple snails and a pleco. The snails all have significant shell damage. There were about 40 apple snails in the tank. I only had enough to buy 3 snails though. The first one shell's is just about see through. Actually on the upper part of his shell, I can see through it to his body. Another one has large holes at the bottom of his shell near the trap door. The third one has a badly detoraited area all around the spiral of his shell. I had them munching away on Caltrate last night. This morning I'm making them snail jello. This are just little babies, about the size of a dime if not smaller.

I also bought a juvie pleco. He is less than 1/2 long, has a very sunken in belly and lots of red area's. I have a lot of research to do on this little guy. I think its septicism (sorry about the spellling). He wouldn't go near the zuchinni last night. I'm going to put in another piece today.

In the meantime, would I be better putting all 3 baby snails in a separate 1 gallon "aquarium." The problem with those is that I can not monitor the temp as well as I can in the bigger tank but I could make sure that they had a lot of caltrate or should I just try the snail jello for now with the zuchinni?

Walmart makes sooo much money off fish. So I doubt that my $12 would stop them from selling fish. I know that if everyone thought that way blah blah blah but I would have felt guilty if I left them there. I had just had to euthanise my 10 month old cat so I needed a distraction. I'm broken hearted over losing my baby and taking care of the snails and pleco is helping me by distracting me.

Snails are more active now and the baby pleco looks great. No more red and his belly is nice and full.