male not colouring up

[borderboy]

Hey guys,
I've had my a.cacatuoides just over a month now (1m 3f) and my male hasn't coloured up at all. I thought he was a subordinate when I bought him but given a few weeks he would colour up but it just hasn't happened. Any ideas?
I have a 3ft tank which the apistos share with some corys, Ottos, silver tips and glowlights. The females all seem to have set up territories quite happily and the male does display a little to them but he isn't the bold dominant male I thought he would develop into. Thanks in advance.
Apologies for the poor quality picture

 

[gerald]

He probably just needs more time, assuming he's eating well and otherwise acting normal. If he's not eating much, or looks thin, rapid breathing, bulging eyes, cloudy fin edges, etc, then he might be sick. The photo is not clear enough to see these things.

 

[borderboy]

Thanks. Yeah he's absolutely fine health wise. A little skittish at times perhaps but it's not like he hides all the time. I've just not known a male not to colour up before. Hopefully it is just a matter of time