2 New Gourami Is This Behavior Normal?

[Plecc]

Hi,
Just got myself two Gourami for my community tank, (great fish, so colorful!) a blue and a gold, as far as i know they can only be sexed by the length of there dorsal fin is this correct?
Both my Gourami are about 3 inch in length with the golden one being a bit larger in all dimensions and with a dorsal fin double the length of the smaller blue Gourami. (i think the gold one is a male but not too sure) They all appear to get on great in the community tank, but whenever i go to feed them or even just stand next to the tank the smaller blue Gourami (which i think is female) begins to get aggressive towards the larger Golden Gourami and relentlessly chases and nips at his sides, which often stops when i leave the tank, then they appear to be the best of buds again and spend allot of time together, but it may be that they are just keeping an eye on each other.
Is this behavior strange?
Is there anything i can do to stop this?

for tank stats check my info.

Thanks,

 

[Littlemonkey]

Have you any pic's so we can tell what sex you've got and what type.

 

[crazychris]

Hi. Yes it sounds like your golden is male and your blue one's female. As well as being much shorter is the blue one's dorsal fin rounded as opposed to the golden one's being pointed?