Odd Gourami

Question
Thank you. I see what you're saying but your response makes me wonder if the colors showed well in the photo. You're saying that the front half is the defect, but the front half matches my other blue gouramis, it's the back half that's odd. The front is a nice healthy blue, the same blue as the two I bought at the same time, but the back is so black that you can't see his dots. Is that what shows in the photo as you saw it? Have you ever seen one like this? I've had them turn gray for a short time and turn back, but never one that was half-black and stayed that way. BTW, I have six tanks(fresh,salt and brackish),too many fish to list and all stay very healthy, so I think I can rule out stress or water quality.
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-----Question-----
Please see: http://gallery.pethobbyist.com/index.php?photo=311500. I've asked experts at three fish stores and no one knows why this fish is like this.
-----Answer-----
Hello Danni-

As you may have noticed, gouramis can change color depending on their mood and their surroundings (like cuttlefish and octopuses.) They do this by making use of the photoreceptor cells in their skin, which can be turned on and off to make different shades, colors, and patterns appear and can change again in  seconds.

My best guess is that your fish was born with some kind of congenital defect that disabled the photoreceptors in the front-most half of his body (which is why he's pale there.) Gouramis with working photoreceptors show patterns like those that appear on the rear-most half of your fish.

This defect (possibly x-inactivation) most likely occurred while the fish was still in the egg, and as his cells divided, the cells with the defect passed it on to the daughter cells (explaining the cut-off between the normal cells and the pale cells.) This type of defect can be seen in calico cats that have patches of two different colors.

This defect probably became apparent around the sexual maturity of your fish (which is usually when photoreceptor activity is greatly increased.)

That's my best guess anyways. Sorry this is so scientific - That's what you get when  you go asking biology questions to a biologist! :)

-Amber Worman

Answer
Hello again-

Ah! It's a blue gourami - I thought it may have been an opaline gourami like my boys. In that case, just flip-flop what I said about front and back orientation (and in this case, his photoreceptors would be stuck in the "on" position rather than the "off" position.)

I've seen a gourami with this defect splotched throughout his whole body, but never half and half so perfectly like yours.

This shouldn't affect his health in the least, and it's perfectly possible that what I mentioned is the cause behind the color. I can't really think of anything else it could be, so don't worry -  You're being a great "mommy" to your little guys!

Sorry about the confusion.
-Amber Worman