I made my tank background on my printer. Depending on the size of your tank you would only have to crop it to a specific size and then either print it at home or send it to office max for oversize printing.
I can help you size it if you want, I have the software to do that easily, just tell me the size you want it and I can e-mail it to you.
I put min on with double-sided scotch tape.
My yellow HMs King Willem-Alexander, Queen Maxima, Rosie, Pepper ...and ten thousand children of Willem and Rosie (it is really about 80, but it seems like ten thousand).
RIP Guppy... The little fishie who inspired me to breed bettas.