Empire Gudgeon not coloring up. Why?

[FishBR]

I got a Empire Gudgeon (hypseleotris compressa) juvenile pair six months ago. They have grown huge and healthy. However, the male has not developed any coloration. No red, just a boring brown.

My water parameters: temperature 75F (24C), PH 7.5, GH 285, KH 113,

My only explanation is that males color up only in the presence of another male, but that is just a guess.

Any experiences with them or hints?

Thanks in advance.

 

[Colin_T]

They take time to mature (usually 1 year but sometimes up to 2 years). Males only show good colour when displaying to other males or breeding, and they don't breed very often in aquariums. Most of the time they are drab brown with a few pales black dots on their fins.