i have a plain black backround on my 75 right now but i cant ever get it to stay on or go on nice and smooth is it worth it to have a backround does it help the fish should i change the color or just leave it off any help would be great

it's not that difficult to get a background to stay, just use tape on each corner and on the top and bottom.

a black background gives the impression that the tank is deeper than it actually is, i.e. makes it look bigger. I have a black background on both my tanks. The last thing you want is seeing a brightly colored wall through the tank.

i also beleive that a background is more desirable than no background. however if all you want is a black one i think the easiest way is to simply paint the back of the tank black(on the outside of course)that way yuo never have to worry about it comming of unless you want it to.