My observations, as your response is sensible and deserves answering.
How long have those blue rams been living? A normal lifespan, which is said to be 4-5 years, has, so far as I understand, only been possible with warm water as the fish is evolved to live in. My pair back in the 1990's did not last more than two years, in a tank at 77-78F, and I now know why. Mikrogeophagus ramirezi inhabits the waters of the savannas, where day temperatures average 40C in the shade. One collection measured the air at 31C (cool for the region) on an overcast day at 10 am in the morning; the water at that time was 28.5C/83Fand that was at the "coolest" time of the average day.
Second, what is Bradley's level of research/biological study? A rhetorical question, but there are a lot of hobbyists--and some very good ones otherwise--who have not studied fish biology and physiology, nor their habitat environment. Those who understand how a fish "lives" can easily see why something like temperature is so critical to the health and functioning of the fish's life processes. I would also mention that every reputable site will agree 99% of the time on such issues. The rest of us learn from these people, that is how society has progressed through the ages, learning from the wisdom of those who do the studies.
As 3-spot gourami have been mentioned...this is one of the most aggressive of the medium-sized gourami species. The 3-spot, blue, gold, marble, cosby, opaline...all these varieties are the one species Trichopodus trichopterus. As with any fish or animal, there can be exceptions to the norm, but normally this species is on the rough side. We had a member here a year or so back who had a female gold gourami that killed every other fish in the 90g tank and had to be separated. Just a caution.