Hi Pat,
I join the line of those admiring both your fish and the tanks and all I can say is well-done!
I have a few questions though. In the home tank, what's the total flow of water through the filters and through that little marine-like current thingy - which I can't remember what it's called, not even in Hungarian. Just by looking at the sizes of those things, I would assume that it's close to the 500 gallons/hour rate, which seems a lot to me. And by a lot I mean: A LOT. Just to compare: my big one has a 15gal barrel filter under it, driven by a single Hydor Prime P20 canister filter, rated at 700 liters/hour, but I assume it barely does half of it.
One evening, when everything's calm, the fish have been fed, just unplug all the pumps for as long as you think it means no harm to the filters (30 minutes should probably be alright) and see if you see any difference in the way the fish behave. I may be completely wrong, but I would be surprised if they did not react to it. Also, if you see them spending most of their chill-out time in one spot as a group, insteaf of sharing the space available more or less evenly, they are quite likely to be hanging around where the currents are not as strong or kill each other out. My Xingús line up along the 8' long back-wall of the tank after feeding and never ever group up, only when I open the lid and feed them. A friend of mine keeps a group of 7 Heckels and after he'd quartered the total flow in their similar-sized tank to yours, his fish looked like they were replaced for a group of happy ones.
Also, looking at the pics it appears to me that the Reds are trying to stay out of the way of all the other fish. Is that really so or is it plainly accidental?
As for a background colour for the blues... How about a shade of blue similar to my background? It contrasts the base-colour of the fish quite nicely, while the reflected light makes the blues blue.
I absolutely like the idea of this rolling diary and will definately keep an eye on the updates. If the water and the food are o.k., I'm expecting an 'Umm... think I may have a pair"- sort of a post within 6 months or so.
Nandi