Ah okay I need auto water changes too.. 🙂 Chocolate gourami are my wife's favourite fish, try'ed Sphaerichthys selatanensis and vaillanti, but both species didn't last really long. Kept them in our bedroom tank were water changes are quite a chore so it was easier to do big ones instead of a lot of small ones..
I've quite fancied Samurai (Vaillanti) Gourmai for a while, simply for their unique colouration (Particularly the females) - not sure how well they'd mix with my Chocolates though, and they're not widely available in the UK (though the guys at my local Maidenhead Aquatics did tell me they get them in occasionally).
I'm a long way from being an expert, but being a blackwater fish, I think they do best is soft acidic water. They are an easy fish to stress, so I think a high planting density and lots of floating and structural cover is essential too. Their colour changes visually within seconds if they get stressed, going from deep dark brown stripes, to almost a very light tan colour. That said, twice I have also seen individual fish pulse their colouration from dark to light and back to dark over a period of 10-15 seconds, when schmoozing up to another fish (presumably of the opposite sex) - I've not been able to 100% identify which is male and which is female, but in both cases looked it looked like the female was doing the 'pulsing' to the male she was pursuing.
I have found they are also active hunters, and regularly stalk through the plants and moss, occasionally darting at something they've spotted. That's no doubt been a detriment to many a baby Neocaridina, but I also have scuds (Hyalella azteca) in my tank, and I suspect the Gourami's are chiefly responsible for keeping their population in check by hunting their offspring. So it's always worth considering adding those as an extra food source, and to promote natural behaviour.
Finally I also feed lots of live food, which I think helps promote robust health in most of the fish I keep.
