I have a friend who specializes in gouramis, with a bunch of tanks. I have had the chance to watch this one at her place, and to get her impressions.
They tend to the expensive because they are extremely delicate softwater fish, and as such, are a challenge for breeders. They act aware of where each other is, but don't seem gregarious. Unfortunately, she likes smaller tanks, and the price of these fish around here makes buying a group difficult.
Another friend, a really skilled breeder with the neatest, most organized fishroom I've ever seen, had a large tank with 10 S. osphromenoides, the standard chocolate gourami. He could barely keep them alive. He had soft tap water and did his water changes religiously, but one by one, the fish died. I got 3 of them once, and had them die off soon after arrival. I think my set up was good. The Genus are on my mental list of fish to avoid.
It stays very small. I just looked them up on Fishbase, a useful science site, and it says they have been observed in pairs, in wood and leaf litter. So a warm, shallow littered tank, probably at least one metre, 3 feet across the front, and live food. A larger tank would be better, with no tankmates.
They seem closely related to Luciocephalus, the pike gouramis. They were the last predatory fish I kept, as I don't like feeding fish to fish, and they could not be weaned off live food as I thought they could. Sphaerichthys are at least micropredators, but they share that focus on moving food.
