Plastic-like film on glass of tank


I have noticed a plastic-like film that is covering the inside of the glass of my tank. I began noticing it when doing a partial water change because the disturbance would cause this mystery film to start breaking off and it almost looked like floating pieces of plastic wrap. When I'd touch it to grab it, it breaks into smaller pieces (it's very fragile). I'm starting to notice the intake of my filter has a build up on it because it's trying to suck up the loose parts up but the bigger ones can't pass through.

Has anyone seen this before and know what it might be? I'm worried it will harm my fish, thanks!


Take a picture!

I had something like a white net of goo that surrounded my driftwood when I first placed it in my RCS tank, though it was a bacterial bloom. Which might be what that is.
  • Thread Starter


Because the film is plastic-like its see through and my camera doesn't show it too well :-/

Imagine the thin plastic that covers a pack of cigarettes, it almost looks like that. In fact that's what I thought it was when I first saw a loose piece floating around (even though I don't smoke lol), and when I went to get it with my net, it broke into smaller pieces. Now I'm noticing a lot of it on inside of the glass...blah!!


Maybe it is some glossy coat that is coming off suddenly. I've never heard of that though.

BTW- edit and fill out your tank's profile so we can understand better!


Might be some sort of algae, although I haven't heard a description like yours before. Cyanobacteria will form sheets like that but it is blue-green.

Thai Aquarium owner

Could it possibly be the protective film that is placed on the Acrylic panes before manufacture ?
Maybe some body forgot to remove the stuff, and now its starting to break down
Just grabbing at ideas


Going to take a guess here and say that you haven't been cycled long, or you're still in the cycle. What this sounds like is a bacterial bloom that you'll find as you're nearing the end of a tank cycle and then a couple of weeks after. Would you post your water parameters?

The good news is that it just looks bad, but there doesn't seem to be any issue with the fish. I've had it happen on a couple of tanks (and it's going on right now with my wife's Fluval Chi) and it typically lasts a couple of weeks before finally going away.

You can scrape it, but chances are that it will come back pretty quickly. I'd still scrape it and do your standard water changes just for safety's sake, but chances are that it will go away on its own still.


It's definitely not a bacterial bloom. Bacterial blooms are a cloudy white and can visually be seen in the entire water column. Heterotrophs reproduce so fast that they cannot attach themselves to the surface of the water, which is why it can visually be seen.


Could also be mineral build up.
How long has tank been set up and is it cycled ?
What are water parameters ?
What is your water source ?
What do you use for a dechlorinator/conditioner ?
Any meds or other chemicals added to tank ?
What size is tank ?
What type/kind of filtration ?
Air stone(s) ?
How much /often are water changes ?
Is the tank planted/non planted ?
Do you vac substrate during water changes ?
Occupants of tank, type and how many of each ?

Answering these questions and any other info you can add about the tank will help us better understand what is/may be going on.

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