[Anda]

In the pictures below are two patches of the same species of moss, less than 20 cm apart. One is nice and green, the other one turning yellowish brown.
Any ideas what could be wrong? Since they are receiving the same treatment, I thought maybe one patch is missing a nutrient?

 

[HollyB83]

My first thoughts would be access to light and water/humidity. Is one in a more well lit area? How about access to water? Is the one that's yellow receiving more or less water than the lush green one? How humid is your tank? Do you know what species of moss you're working with?

 

[Anda]

Hi, yes the yellowing patch receives slightly more water and light. 25 000 vs 15 000 lux (measured with a phone). This is just Java moss. Maybe Java does not enjoy intense light?
I will try to cut back the yellow and see what happens.

 

[gzollinger]

I think everything is perfectly fine. As your green moss gets older and the gametophytes get longer, the non-vascular stems will be more brown on that moss then green. I bet if you trim the brown stuff back to the surface and lighter green growth will come out. At least that is what I think is happening from the pictures. (warning, over generalization about to come out)...I think a lot of the acrocarpous mosses tend to keep a more overall green look then the pleurocarpous mosses.

Also, I am not sure that is java moss. It sure looks different to me then java moss I typically have seen growing terrestrially.

 

[Anda]

Thanks both, I will see what happens.
It has been really difficult to get a hold of mosses up here, will get more closer to summer and more of the recommended types above.
Not sure it is Java moss either, there were some others blended in as well, but all initially bought as aquarium moss.

 

[gzollinger]

Thanks both, I will see what happens.
It has been really difficult to get a hold of mosses up here, will get more closer to summer and more of the recommended types above.
Not sure it is Java moss either, there were some others blended in as well, but all initially bought as aquarium moss.

Honestly what you have is WAY nicer then Java Moss, at least to me. Java moss tends to look sort of stringy and dirty to me when grown in a vivarium.