How can I clean the inside of my glass without removing my fish


New member
I have recently acquired a second hand fish tank which i cleaned before setting up and the glass looked clean and was no sign of algae.

I now have a few fish cycling my tank, but the glass seems really foggy. I have tried to scrapping the inside of the tank with a razor blade but this hasn't helped.

Can anybody suggest another way to clean the inside of my tank without removing my fish!


New member
Cycling with fish is very old school and not very nice to the fish.

As for your glass, its most likely etched, which means that the surface of the glass is damaged and there is nothing that can be done about it.


Premium Member
It's also possible that the water itself is cloudy.

As an aside, there are much better/cheaper/safer/more humane/easier ways to cycle the tank than using fish. I like to just feed the tank as if there are fish in there. Some people just a piece of shrimp in from the grocery store.


12-5 Chiefs record
My guess is the water is what is dirty. Is it a green or whitish color? Carbon should help, if it is green i had good luck with a uv light.


Team RC
I'm sure he/she wasn't aware of other ways of cycling the tank. Now that there are fish in it, they're basically stuck there until it's cycled unless he has a friend that can take them.

To the OP - watch your ammonia and do water changes or use prime/amquel to keep it down while your tank cycles. This may slow the cycling process, but as others have suggested, it's the humane thing for your fish. You can also use a bacteria supplement like Dr. Tim's - no personal experience, but it may help.

To the original question, what do you have in the tank? How long has it been running? Was the glass cloudy as soon as you put water in it or did it become cloudy? If the glass is etched, there's nothing that can fix it. If it's the water, then it's a different problem. Everything else that might grow on your glass at this stage of the game should come off fairly easily.