YoYo loach problem?

[mattskims]

I have two yo yo loaches in my tank, each of them are about 2 inches long. One of them is very distinct and distinct in its coloration between the black and gold markings. The other one however seems to have a "faded" dull look to it. Both are still very active, even in the daytime, and eat well and have not changed their demeanor at all. I can not find any other signs of distress of unhealthiness. Is this coloration a disease or some sort or something I'm doing wrong? Please help I love these guys and would hate to see them upset or worse dead. Thanks

 

[Aqualung]

How long have they been in the tank?

 

[mattskims]

they have been in the tank for 2 months now. The water has always been 78 degrees and ph is 6.8.

 

[Aqualung]

Ok, so that rules out stress from introduction to the tank.

Is there an extreme difference in the coloration between the two, or only a slight difference? If it's only slightly dull colored, it's possible that it's just genetics. There will always be some (even if very slight) variation between fish of the same species. Also, perhaps there is an age difference(?) Does the duller one get picked on at all, or stressed in some other way?

For what it's worth, my dwarf loaches all looked pale when I introduced them to the tank. As you probably know, it's common for fish to become pale in color when stressed. Now that they are settled in, 4 of them look identical, but one is slightly paler in color than the others. I figure it's either genetics or age - perhaps a bit of both.

 

[mattskims]

Thanks for the info....im hoping that what it is.....its not a huge difference but it is noticable, I was just concerned. But like I said, the one doesnt seem to be unhappy or unhealthy in any other way so hopefully its just age and genetics.