Serpent with damaged arms

[Tennyson]

I got abrown harlequin serpent star about two weeks ago, about four days later, a really small part of its arm was missing. Now, I think all parts of the tips of its arms are missing. I'm pretty sure it will live, but what is causing this? I also have another serpent, yet this one isnt missing anything.

All replies are appreciated and thanks in advanced

[irishrose302]

what else do you have in your tank?