weird mucous on water

[zimmerb8128]

i've been cleaning my fishs tank each week. It is a plastic 2.5 gallon tank with just one fish, a heater, and a peace lily sitting at the top of the water. I've had this same set up for over a year but lately, this weird mucousy film has been developing at the top of the water. You can pretty much pick it up off the top of the water, its super gross. I cant get a picture of it because its clear but i want to know why this keeps developing. I used to use a water clarifier and i thought that maybe it was the reason this mucous keeps developing but the last time i cleaned the tank i didn't put any in and its still there. Any ideas?

[LittleFish2012]

I know exactly what you're talking about, and I seem to have that same problem with some of my tanks too. Oddly enough, there is no rhyme or reason regarding whether or not my tanks are heated.
However, I find that my covered tanks don't have this problem.
I think this might be a film of "protein scum".

[Myates]

Excess protein.. normal and not harmful.. just use a paper towel to scrape it off the surface. Sometimes the fish will excrete extra protein and it builds up.
It's yucky, but it's common.. careful with the peace lilly, as that isn't a true aquatic plant.. but if you've had it for over a year with the same fish/tank then it's probably already settled in.

[zimmerb8128]

thats so weird but at least i know and its not harmful. Too bad it keeps showing up though cause he wont eat unless i scrape some away.