[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Java fern "melt" observations

Several times through the years people have asked me personally, or have
asked here on the list about their Java ferns "melting" en masse.  They
have mentioned that an entire stand would deteriorate in a fairly short
period of time (although not as fast as Crypts!) but that if the affected
leaves were removed, the rhizomes seemed to recover and produce new leaves.

I don't think anyone has had any idea why this has happened, or what (if
anything) could be done about it.  

I have just experienced this phenomenon in one of my tanks for the first
time, and I have an idea.  I'd appreciate it if any of you who have
experienced this melt would comment on whether my theory holds with your
own observations.

This is a high light/CO2 injected, strong growth tank that has been
neglected recently.  I normally supplement regularly with KNO3 in this tank
as well as trace elements, but recently have slacked off (I _know_ this
never happens to any of you!<g>)  and let things slide.

I noticed a few leaves going, and not in the "typical" pattern of older
Java fern leaves.  These leaves were developing large mushy brownish black
areas, mostly on the lower part of the leaves and on the petioles
themselves.  New leaves as well as older leaves were affected.  "Normal"
Javas and 'Windelov' were affected, 'Tropica' was not affected to nearly as
great an extent.  Since I still didn't get around to doing anything, the
complete  stands of both normal and 'Windelov' types deteriorated

Today, I finally got around to working on the tank.  I did a water change,
and removed all the Javas.  I removed all damaged leaves. (this meant _all_
'Windelov' leaves and all but about 3 normal leaves)  There were also large
sections of mushy, rotted roots, and I removed these as well.  The rhizomes
felt firm and were green, so I have replaced these in the tank.

I did some water tests just before I did the water change, and found that
although there was still measurable iron in the tank. (which, since I used
a complete trace element supplement, probably means that other trace
elements were also in adequate supply)  There was _no_ measurable nitrate
with a low range test kit that measures down to .2 mg/l.

My guess is that the Javas, which have no access to nitrogen via the soil
(they are all attached to drift wood) were unable to compete with the
faster growing non-rooted plants and those with access to substrate
nutrients, and that this lead to the massive failure.

There was some loss of older leaves of some large Echinodorus and a slow
down of my Riccia plague<g> consistent with low macronutrients.  But
nothing but the Javas took such a big hit.

I dosed the tank with both trace elements to make up for the water change,
and KNO3 as well.  I'll let you know how the Javas recover.

Any comments?

Karen Randall
Aquatic Gardeners Association