My Gourami Changed Colour?

[Dolphindolphin]

I have two female blue gouramis in my tank and I recently introduced a yellow male, since doing this the smaller blue gourami has changed colour and become a lot darker than before. Can anyone tell me why this would be?

 

[DreamertK]

The smaller gourami is angry there's another gourami in the tank. She's showing her aggression towards it and might end up attacking it. Blue gourami can change their color very often and very fast depending on their mood, pale can be fear/stress/sickness while dark is aggression/anger/mating.

 

[TallTree01]

^ +1

 

[Lunar Jetman]

How big is your tank? If it's too small they may be getting quite territorial so you might have to think about which ones you want to keep.