I first noticed it a couple days ago and thought it might be ick

but now i'm not so sure because now it looks like they have swam through halloween cotton spiderweb stuff and have it all the way down their back. only problem i have nothing like that in my tank. I'm not sure if any other symptoms are there because i work nights, and so far haven't been able to see them active, just the usual laying around looking bored. none of the other fish in my tank are sick and all are very active. Thanks in advance for any help.