Is my cory sick?

[CozyCat]

Hi, new fish keeper here.
I have a group of six peppered cories in a 12 gal planted aquarium with some guppy fry.
Had three to begin with and recently added another three to the group. One of the new ones has a bent spine and is behaving a bit odd.
He is very inactive, but can swim ok when he wants to. The other new fish are fine and are cruising around with the others, it's just this one guy. Maybe he's deformed??
Most of the time he finds somewhere in the mid to top of the tank to rest. Sometimes I find him resting vertically and think he's dead until I see the gill opercula moving.
He is a bit on the thin side and I can't say I have often seen him grazing around for food or with the other cories at feeding time.
Would really appreciate some advice on his condition so I can help him. Couple of pictures of him below.

Thanks

 

[itiwhetu]

This fish is deformed so you don't know what else is going on with him. Always select your fish carefully and avoid any fish that looks like this. Tell the people at the LFS what fish you want.

 

[CozyCat]

This fish is deformed so you don't know what else is going on with him. Always select your fish carefully and avoid any fish that looks like this. Tell the people at the LFS what fish you want.

Thanks for your reply itiwhetu. I'll keep that in mind when purchasing fish in future