Gourami Has A Lump & Stringy Poo

[scousemouse76]

i have a blue gourami pair, not sure if they are powder or sky blue.The male has a lump where his tail fin joins his body, shows right through both sides of his tail.I've read some other posts on here and i am pretty sure it's an ulcer.From reading other posts, his odds don't look very good, as he has gone very quiet and is hanging around the heater not far below the surface. Should i put him to sleep?
i'd of put some pics up, but having trouble finding the attatchement thing

 

[WILDER]

Ulcers are pink or red with a circling of dead white tissue around the edges.
Is the lump soft or hard looking.
Long stringy white poo means constipation, internal parasites to bacterial infection.
Is the anus red and inflamed or enlarged.
What do you feed your fish?