Colour changing gourami?

[Raisen]

i just got a female and male gourami from my friend. i put them alone in a tank then three days later i noticed a bubble nest. but today there is no bubble nest and the males colour darkened alot. he looks almost all black.can someone tell me why he is black
they are very healthy and they eat.

 

[V227]

R.
If you don't see Rapid breathing, white spots, fine yellow specs, or a white film like growth on your Gourami, then likely there is no disease. If your water parameters are normal and the fish are eating, swimming and generally acting normal then the color issue might be hormonal changes associated with mating. A lot of different species change colors depending on their mood.

 

[Andy Sager]

Different Gourami species change into breeding colors when they are preparing to spawn.
For example, Male dwarf gourmis get a deep blue throat, Honey gourami males develop a dark band along their underside as well as changing from a tan-ish color to a golden honey color. So depending on what type of gourami you have will tell you if this is normal. As for the disappearing nest, Gourami need quiet waters for their nests to stay in tack. They also need a little humidity as well so if you don't have a lid on your tank and you have rapidly moving water, that can explain why the nest disappeared.
So we need a little more info ( as to type and setup) to help us help you.

Hope this helps