The outside of the backwall of my 125G tank has been painted a deep forest green.

I am a huge fan of aquarium backgrounds make from real rock, like the one I am using in my 240G tank. Personally, I don't think there is anything that comes even close aesthetically, but I wanted to try something different in the 125G tank, and I wanted to be able to move this tank again, in case it had to be put in a different position inside my house, or in case I had to move at some stage in the future. Due to the weight, I don't think any tank of 100G or over is ever going to be shifted again one a real rock background has been installed, but I have not yet had the opportunity to test that hypothesis!

The color is rolled on to achieve a very even effect similar to spray painting.

With that in mind, I decided on a comparatively simple background option; that is painting the outside back wall of the tank. By far the most common color choice here seem to be black, which offers a poor color contrast with my chosen fish - Tropheus sp. ‘Black’ (Pemba Orange Flame), which are mostly black. This is closely followed by baby blue, which I guess is supposed to be some sort of ocean blue, but in my opinion is reminiscent of a 1970s swimming pool - yuck! My wife came up with the brilliant idea to use a deep forest green. I haven't seen this in any other tank yet, but I reckon it looks fantastic in my tank!

Putting on the first coat.

The color is rolled on, and you will need 3-5 coats in order to achieve a good cover. The stuff dries quickly, allowing you to put on 2-3 coats per day, which makes this a comparatively painless procedure, and as far as aquarium backgrounds go, painting the backwall seems to be the method with the best impact to effort ratio!

No need to be alarmed if the tank looks like this with just one coating of paint. 3-5 are needed to achieve an even look.

Near the top rim of the tank a gap developed in the paint even after 3-5 coats of paint. I figured this would not be a huge deal, as long as no light was coming through this gap, which would make it really obvious. Hence I covered this area with black electrician's tape, as seen in the small photo on the right.

Gap in the paint near the top rim of the tank - before (top) and after (bottom) covering with black electrician's tape on the outside.