I have a 200 liters (100 cm) aquarium. When I bought it I didn't know it could not be placed in front of the window so it grows algae now.

The algae is green and rough. I cannot remove easily. I can only remove with my nails.

The tank doesn't have a background picture(wallpaper).

I'm wondering if putting a background picture and/or a curtain can help deal with that.

It will be painful take off the water and fish in order to move the aquarium to a new place.

  • I have exactly the same setup and could lower the algae level temporarily, but never constantly (was as bad as pets.stackexchange.com/questions/12152/…). In my case adding an undergravel filter solved the issue (a 100x larger filter just removes everything from the water, see pets.stackexchange.com/questions/15506/… for details). Of course that almost is as much work as moving the tank. I succeeded to install the undergravel filter while the aquarium was running. Jan 9, 2017 at 19:27

2 Answers 2


Having a opaque background will help if the tank has his back at the window. If it is not the case it won't help with the algae. As long as your tank sit in direct sun light you will have excessive algae. There are a few solutions that might help a little bit but the only good one is to move the tank where it is not in direct sunlight.

Here are some ideas

  • Have an opaque background around the back and the side of the tank
  • Add real plants, they eat the same nutriment as algae, but generally algae are more effective to get those nutrient
  • Add livestock that feed on algae (snail, shrimp, some fish, etc.)
  • Deal with it by scrapping it regularly and knowing it will need to be redone in a couple of days
  • Yes, it has the back at the window. I printed my own background with bond sheet ( I printed the pages and joined them). Is it considered opaque? I will also get a curtain as long I get some extra money.
    – Murilo
    Oct 18, 2016 at 20:46
  • If you put it directly on the window, do you see through it? It sure is better than nothing, Any cardboard should do (at least temporarily) so you could use a cereal box or any other cardboard box really
    – Rémi
    Oct 18, 2016 at 20:50

You can add a curtain or a background as you said but you would need to keep it closed for the most part, worth trying if you don't want to relocate it.

When I was working at our local pet store we would use razor blades to scrape the windows (just don't cut yourself), came off really easy. I never found any of the pet store algae scrappers useful for the really hard algae you speak of.

Some people will purchase algae eaters such as apple snails or plecostomus, I find they do help some but they wouldn't be able to keep up with your problem and they also grow really big.

  • Use a rubber scratcher near the silicon joints since even slightly touching it with the razor might harm them - if not the first time, then some of the many time you'll have to use it. Jan 9, 2017 at 19:22

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