Since I moved them to my outer room the average temp in the tank has dropped from around 70 to around 65. Also, I've doubled the feeding in the last two weeks from around 1/2" square bloodworms to the same twice a day. I continue to feed live white worms once a week or so.
I've also added PVC pipes in 1" and 3/4" diameters, closed on one end. They've been ignored entirely.
On the bright side, I have two females who are getting rounder, and I've seen increased cave building activity (as usual, under a flat rock) by my youngest male. If I don't get some guarded eggs in the next week or two, I'll pull my fattest female and nicest male and put them by themselves in a 5.5 gallon by with sand and one nice flat rock.
While these gobies are very peaceful, the males do spend energy watching each other closely, especially when building caves.