My Cichla Monoculus can change color like chameleon

[purpleblau]

Hey guys,

I just got 4 really nice cichlas (12-14" long). Their black stripes can fade away and come back like a chameleon.
I don't know if this is normal. Especially, when they are scared, their black spots and strips almost completely fade away instantly. After a while, they come back. The overall body became much darker too. Interesting!

Is this known to you guys too?

 

[giar]

yes, when I did my 50% WC, their colors became slightly pale, and 10minutes after WC, they went normal.

 

[purpleblau]

thanks, I figured now, if they get stressed or something, they change their color accordingly too. They only show the vibrant yellow, orange and pure black, when they are happy or they are feeding.