Not Quite An Emergency But An Upsetting Issue

sadly by gourami suddenly died tonight, he was swimming around happily, i went to the other room for 20 mins, came back and he was dead on the bottom of the tank, water is fine Ammonia 0, Nitrite 0, Nitrite 0.5
 
in the tank i also have some tetras (neon, glowlight and black phantom) and a molly
 
the gourami had been in my tank for 3 months, no signs of infection, illness or stress, happily swimming about being the biggest in the tank, was the pride of my tank, im actually heart broken, and i dont know what caused it!
 
 :'(

Sometimes it is hard to pinpoint a reason for a sudden death. It may simply have been a stroke or natural causes or maybe an internal parasite. I would do a partial water change and sterilise your net. Just keep an eye on the rest for the next few days and look for any other unusual behaviour.

Sometimes fish can just die without an apparent reason. Looking at the photo, nothing pops out as being wrong with him. 
Monitor the rest of your fish for a few days to make sure there are no further deaths.
Also, it may pay to do a waterchange, just to be sure.
 
Sorry for your loss

thanks guys, i was going to see about getting someone else to go in my tank too on sunday, but now with a sudden death, im not sure if i should...

I'd hold off just to be sure there is nothing going on. Things normally show up within two weeks.