Need advice on background colour

I am in the process of painting a background on MDF. I am aiming for a kind of mosaic tile effect and am just about at the point where I am painting the "grout" lines. My original plan was to go for a silver grout colour, but I thought I would stand it up behind Tequila's tank before I started just to see if the idea was going to work at all.



Now I am thinking I might like it more if the grout lines were a dark grey or black, but at the same time I kind of like the light colour for them, I just think the light draws too much attention to the background and the rest of the viv gets lost. Opinions?

I think a mid/dark grey would look good. Otherwise, like you said, it pulls too much attention away from the viv. I think black would be too dark though, you'd have a harder time making out the darker colors.

What about a dark brown to match the eco-earth? Or I kind of like the light blue tips on that plant right in the middle, what about a light/mid-tone blue grey? Don't you love it when people vote for option other than the multiple choices given?
I agree that white steals the show, though it looks great, and black might be a bit dark.

Can't wait to see the finished product, that looks really cool!!

Thank you both for the suggestions. It hadn't occurred to me that a black would be too dark, but I think you are correct.

I hadn't thought of a blue-grey either ... hmm. I may have to experiment with that.