Fish and its reflection

[dendro982]

I had a fish (lion, file, tobby puffer) that swam a lot, facing the side glass, not covered by background.

Now I'm setting a new tank and trying to figure out, will it be a good or bad idea to cover 3 sides of tank, except front glass, by background to prevent fish seeing reflection - own or of the tank, as a new territory where to swim.

I thought about open from 3 sides tank - see through version - with rockwork at the middle, but afraid, that file and lion will be stressed by being in the open (even with hiding places).

I was thinking about making stone paint (on outside, Fishy Review - Aquarium Reviews and How-tos ) black bottom with grey walls. Family members disagreed, because it will be not removable, if this don't work. But backgrounds from LFS - blue and black are glossy and may provide reflection.
If make stone paint background on separate surfaces (plywood?) - adhesive tape, holding them, will be visible, and tank is in the middle of basement.

Your thoughts?
I'm trying to avoid flat rock walls on these 3 walls to maximize swimming space, this is 125g long tank for 2 large and 1 medium fish (tassle files and antennata lion, have 90g as back-up in case of troubles).

And while aesthetics is good, fish's mental health is more important.

[leebca]

As far as I know, the glass, whether backed by paint or other background will still cause a faint reflection. It's usually a matter of whether or not the fish pays any attention to it.

[dendro982]

My fish paid attention, and a lot of it , but only predatory or partially predatory, not the damsel fishes.

May be not blue or black background, but with photo print of rock or corals will distract fish from looking at reflection?

So far I can't imagine the other way to prevent this behavior, alas.

[leebca]

That idea is a possibility, IMO.

[dendro982]

Thanks!
If any other ideas will come later - post, please.