White Balance and the Nikon P80

[Acronuts]

know guys but this nikon works great for all my needs.
I do have one problem though.
When I adjust the white balance and take shots of my tank the blue is almost completely taken from the coral colors.
How can I adjust this?
Can it be done on the camera with settings?
On this camera the white balance is availabel in "P,A and M" modes. For the tank I am almost always in "M" mode with ISO of either auto or 400.
Don't get me wrong I get great shots but would love to show off my blue hued acros.

Your help is greatly appreciated!

 

[gparr]

If you're using a white surface to set your custom white balance, your images should retain the blue clolor, if they're blue. If the surface you're using to set the custom white balance is not truly white, it will affect the resulting image colors. I'm assuming you can't shoot in the RAW format?
Gary