Don't know what happened, Tested my waters yesterday and all was ok, nitrate was about 10-20ppm so scheduled a pwc for today to knock it down abit but my gf has just phoned me as I'm at work and told me my gourami was on it's side at the bottom of the tank not moving only got him on Saturday he looked like he was doing fine all weekend swimming around elegantly as he does and now bam, he's dead!