Wanted to make a background

this is from a mate not mine
Wanted to make a background for my new(secoundhand) 6x2x2.5

Had a look at a few difrent ways of doing it and ended up using someideas from the diffrent ways

Got some poly from the WIZ for free Thanks Mate :D

What do you all think?

Step 1 cut poly to size of tank
cut random picecs of poly to make rock shapes and glue on top of each outher with a small blob of silicone :D

Step 2 go over all the edges with expanding foam The stuff that comes in a preasure pack

Spray random foam over back ground to make outher features

Step3 melt away poly to make caves note spray foam will not melt
smooth down foam with a wood rasp/file
Then when you are happy with the shape cut into sections to fit in tank openings

Step4 render all over with premix cream morta

Step 5 add some colour to next coat (cement Oxide) and do some more use drifrent colours to get the shade you want i only used two
Black & sand stone all done using a brush

Step 6 seal with pond sealer i sprayed it but you can also brush it on

Step 7 Silicone to back of tank
render up the joins
Seal the joins with the sealer and a brush
Instr on sealer say leave for 7 days before filling with water :D

Here are some outhers i have made :lol:

Regards Cobby


amazing. i made a background a few years back....but all i did was stick the shape mounds onto a flat piece and then sanded it and painted with pond paint. my fish had a great time picking at it lol and some of the polystyrene went a bit funny. i dont know why. but it looked good for a long time.

thanks for the diy.
Apr 27, 2009
Middle Earth
This is something i want to do when i build my Rift Cichlid tank (long way down the road) looks amazing
My only concern for use in most of our tanks is the Plecs, is it safe for Plecs to rasp on? give it a few months in tank and i'm sure it will have a nice slime coat/algae growth that most plecs would love to chomp at i'd be seriously worried about my prized pleccies munching on anything like that, i know you seal it with pond sealer but with such an intricate design can you guarantee a good enough covering and with that is the Pond sealer itself 100% safe for the plecs to suck on? :(
Another quick note, if anybody is considering having a go, if you use any kind of cement etc to build up the background i'd advice soaking the piece 1st to leech any nasties Before Sealing only takes a small crack/cut/break in the seal and those nasties will leech into your tank full of fishies!!


Jan 15, 2011
Fantastic log of those amazing backgrounds, totally jealous. . .maybe you should think about giving lessons? I have the the same concern as kissed lips dude about pleco's rasping amd the safety of that? Respect and thanks. :)


Jun 11, 2010
ct ,usa
:clap::clap::clap:WOW! very talented workmanship , and love the hidey holes. bet the fish do too ! nice work , thanks for sharing.