brown patches on mouths, foreheads of yellow labs (pic). diagnosis?

[gregga]

Maybe someone can help...........
I have some 3" yellow labs in a 20G growout tank. The tank has been running many months. Recently they've developed what looks like "dirt" patches around their mouths/foreheads. Fish seem to be swimming and eating normally. I have 9 other tanks, none of which has anything similar. Is there such thing as brown fungus? Here's a pic. Thanks in advance.
http://www.printroom.com/_vti_bin/ViewImage.dll?userid=gregga&album_id=100447&image_id=19&courtesy=1

[Faramir]

I've seen this before. It doesn't appear to be a disease.

IIRC, there has been some association between this discolouration and high nitrates, so you might want to investigate a potential link there.

[gregga]

Faramir....
Hmmm.......OK, that's a starting point. Have you ever heard a name for this condition so I can do some research? Although I didn't find high nitrates in that tank I would like to keep investigating.......Thanks for the feeback.....BTW, what's IIRC?

[JSchmidt]

Many of my yellow labs get this sort of 'five o'clock shadow.' On mine, it looks more black than brown, but the pattern looks similar to your fish. I assumed it was normal yellow labl markings. Lots of folks have reported seeing it.

HTH,

Jim

[Faramir]

Concur. It's not a disease, or a "condition". Ignore it.

[gregga]

Good to know...thanks guys.

Just seems weird that I have never seen these markings in 7 years of keeping Labs, then all of a sudden the markings show up on all the fish from the same tank. Guess we'll keep an eye on things...thanks again for the feedback.

Come to think of it, I have 3 other Labs in another tank that do NOT have the markings...go figure.......Gregg

[Hootchieman]

I have three Blood Parrots that get brownish patches from time to time that do not seem to effect the fish at all. One LFS thought it could be some type of "fish herpes". Hmmm....anyone seen any birth control / protection for fish?:D

[esoxlucieus]

My males get this about the time they are getting ready to breed. When they are dancing the colour is more of a navy or deep Purple. When nothing is goung on you can't see any of the colour.