Strangely enough, the plants I'm having the most trouble with right now are
the supposed "idiot proof" plants: Java fern and java moss. Some leaves
on my java fern are slowly turning brownish/black. I'm not sure if it's the
plant itself or if it's some type of algae on the plant that is causing the
discolouration. I have taken a picture of the most severely affected leaf,
though it looked slightly prior to this picture being taken as I tried to
scrape off some of the discolouration with my finger nails:

Welcome to the "Better Idiots Club", open to all who can kill java
fern and java moss. I'm in the same situation, and posted a
similar message yesterday (the photo of my afflicted Java fern is
he http://web.mit.edu/lovell/www/aquaria/java.htm

I did a search on google groups and found numerous past postings on
this condition, so don't worry, we belong to a big club. Anyway, i
haven't yet found a posting that is convincing as to the cause, but
most agree that removing all the affected leaves - even slightly
affected leaves - will stop further loss. That may mean going back to
the rhizome, but at least you'll save the plant.

So far the explanations for the cause have been:
1- An infestation of blue-green algae (cyanobacteria) that stunt the
growth of the plants in the tank and promote this problem with the
java fern
2- A sudden change in conditions leading to a condition similar to
"cryp melt", but for the java fern. In my case, the light was left
off for several days over Thanksgiving while i was out of town. In
other cases, addition of a new carbon filter or even a water change
have been blamed.
3- A lack of macro- or micronutrients.

Note that none of these are mutually exclusive. I DID notice a lot of
patches of blue-green 'algae' around the time problems began, and i
began adding fertlizer not long before the incident, so perhaps i
adjusted the deficiency to one that promotes the java fern melt. My
java moss is browning now, just like yours, but it was previously
growing like a weed. I think the culprit is me - i was spooked by the
ill effects that adding fertilizer seemed to have had on the java
fern, so i stopped adding it.

I'd suggest you add some fertilizer and see if your moss recovers.
I'm sure more experienced keepers are cringing, but right now i'm just
using some Schultz liquid fertilizer, adding a few drops each time i
change water or each week.

One final question. I currently am not using any fertilizer, but with so
many plants in my aquarium, I'm thinking that I'm probably running low on
nutrients for them. What's a recommended fertilizer for a low light set up
with no additional C02? Not that my oto would complain about an algae bloom


Did you read about making your own PMDD? That's what i'm going to do
when i get the ingredients i ordered.

Good luck. Please contact me if you find more conclusive information
than what i shared here.