I've read about how sensitive they are but I'm yet to see it. Since I got them at a great price I decided to take a chance and see how they'll do in the tank. The water in Texas is hard with a KH anywhere from 12 to 18 and they are just fine.
Their appetites are not affected by the hard water because they eat two to three times a day. When the fish see my son approach the tank they anxiously wait to be feed. The Chocolate Gouramis are not as shy as they were made out to be, maybe it's because of all the plants. They were skittish at first but quickly became comfortable in their new home.
My son and I do water changes right from the faucet with a python so its straight up tap water which contains chlorine and chloramines. The fish are fine with it, swimming around looking for food as we do the water changes. I add prime to the water without any ill effects to the fish. Its been said that they are susceptible to bacterial infections and skin parasites but again they are doing just fine.
As far as dosing is concerned, Connor doses more than EI recommends for some things and the fish are not affected by it at all. He doses extra iron among other things and the fish and shrimps are fine. I really don't know what all the hoopla is about with how sensitive these fish are but it seems like we broke all the rules pertaining to the Chocolate Gouramis with no ill effects. They are happy, playing and eating well.