Dwarf Gourami Developing Sores

hi all
I currently keep my dwarf gourami along with a golden gourami, opaline gourami and some other species in my 75g tank.

I have just noticed today what looks like 2 marks on its left flank. I at first thought this may have been trauma from an attack by the golden gourami (he is a bully) but on reading this forum and taking another look at the dwarf it appears it may be dwarf gourami disease.

I have had the fish for 4 months now and quarantined it prior to adding to main tank. It has not displayed any signs of illness and has always fed readily ( and is still feeding). However it now appears a little listless and just tends to hide amongst plants or behind other cover when not feeding. water parameters are
ammonia 0
nitrites0
nitrates 0
pH 8.0
temp 28c
15% water changes carried out weekly with treated tap water at tank temperature.

It seems like the disease will end up fatal for my fish and don't want him to suffer. Is there anything I can do?

please see pic

Looks like sores caused by poor water quality, potentially triggered by a bite.

I would take the following steps:
1. gradually increase water changes with temperature matched water, going up to 50% once per week
2. medicate with a decent anti-bacterial/fungal medication
3. lower temperature to 22-25C (slowly, over a few weeks)
4. add (more?) live plants
5. separate different gourami species into different tanks, most popular gourami species (and the two you have names above are most guilty of it) have high aggression towards other gourami species and their own kind

i have quarantined my sick gourami in my original empty 26 gallon tank and have medicated the water with king british disease clear potion.

could high pH be the culprit as my ammonia and nitrites are always 0ppm? oh the joys of living in a hard water area!!

No, it's unlikely to be the pH and I have kept them in similar conditions before without problems. It is more likely to be bacteria, hormones and other stuff which has collected in the aquarium water. Large water changes will help eliminate this as a problem factor. Dwarf gouramis are very sensitive to water quality, which is a factor many people forget about.

I haven't used the KB, so can't say anything about effectiveness, but the clean water in the new tank should help.

Unfortunately I had to euthanise my beautiful dwarf gourami yesterday. He was just sat motionless, not feeding and his sores were spreading and I felt that he was suffering.

Couldn't bring myself to bash his head so used clove oil to anaesthetise him them poured alcohol into the jug of water that he was in. It was quick for him once i added the clove oil mix and he showed no signs of distress. He just floated upside down. Sorry for the gory details but I would recommend this method of euthanasia over others as I and several fish specialists i contacted feel that this is the most humane method of ending suffering.

thanks for the advice kat

Sorry for your loss