Poorly gourami

Question
Hi there, I wonder if you can help me? I have a well established fish tank, it's a 9 gallon Biube tank, and in it I have 1 dwarf gourami, and one blood red gourami, as well as 2 adult guppies and about 12 of their babies (they are still proper babies, only 4 weeks old). The temperature ranges from 24-26 C. I check the water every sunday, and today pH is 7.4, nitrite is 0 ppm and ammonia is 0 ppm. My nitrate testing kit has run out and am waiting for a new one to arrive in the post, but last Sunday it was low. The filter cartridge (its a sponge with charcoal underneath) gets changed every 4-8 weeks depending on when its needed. It was last changed 2 weeks ago. I do used a gravel siphon when I clean out the tank. Currently the water is clear, and the stones and plants I have in the aquarium are numerous (the plants aren't real, they are plastic).
My problem is this. My blood red gourami is looking a little worse for wear. His dorsal fin looks like is has become stuck together towards the end of his body and has come to a darkish point at the end, although towards the head end its sticking up as it always were. His tail fin seems to droop slightly and it has a few cracks in it which you can see when he swims. His anal fin seems shrunken but ok and his pelvic fins seem fine. He is still red in colour but looks a little paler especially around the gills. He is still eating small amounts and poohing normally as well (no stringy pooh noted). His eyes still look bright and they do not look pop-eyed. His mouth similarly looks ok. He is still swimming around but not as much as usual. He tend to prefer 'perching' on the rocks and staying still, but he will swim up to the top when fed. Last Wednesday his tummy looked a little hollow but that seems to have cleared up since I've been feeding them their favourite food, some blood worm. The other fish are all healthy, the other gourami looks in great condition and my guppies are all healthy and breeding well with no ill signs noted.
I am at a loss as to what is wrong with him, and I don't want to start medicating the tank with random bits and pieces because I don't want to disturb and upset the other fish.
Please help, I love my fish and don't want to lose him!
Susan

Answer
Hi Susan:  The gourami may have an intestinal issue... which is seen when fish lay around, and generally allow themselves to not look their best...ie... fin clamping, etc.  He may also be the victim of a bully fish... which is indicated by laying around and pale colors being displayed.  If it is a bully situation the culprit may be the other gourami but guppies have been known to pester other and bigger fish too.  I would keep my eye on him and see if anyone is bugging him.... The best thing to do for him is to treat the tank with aquarium salt... that wont harm anyone and then try to feed them several meals (once per day) of live brine shrimp.  The brine shrimp are good for them all and if it is an intestinal issue ... they will help clean him out... keep me posted... dave