Hi there,
I too love Dwarf Gouramis... But the last time I kept them was in 1997.
Back then I was in Malaysia and found that they are very easy to keep but very difficult to raise their fry.
When I kept them, the conditions were similar to Bettas and Tetras. So really there should not be a problem. Right?
However when I attempted to breed them, there was an issue with their immunity. They bred in the thousands but most fry did not survive. This is despite having the best setup at the time (I was living with my Grandfather who was a Discus breeder) and had access to most things needed to be successful with raising fish.
Tracing back to that time, I have read articles about the decline in fish immunity due to some farming practices such as inbreeding and raising fish with constant medication and antibiotics. One article in particular was about Dwarf Gouramis. The author reported what I have also experienced with raising the young. Therefore I suspect the imports we get here in Australia may already have weaken immunity, which makes our job as aquarist more difficult.
More recently I have also had problems with some guppies I have bought from the stores going belly up within a week or two. I think it comes down to luck and proper quarantine before you introduce your new fish into the community tank.