Anubias question

[Laura Wichers <cellostix at wtw_waveform.net>]

I'm fairly new to planted aquaria and am having some difficulty with my 
tank.  It's a 20g high.  Setup is as follows:

Eclipse filter system (no bio-wheel, only filter pad)
100watt submersible heater (set ~76F)
Nutrafin CO2 system
flourite substrate
55w PCF (runs from 9AM to 10:30PM)
total hardness ~250ppm
total alkalinity ~120 ppm
pH ~7.6 (all using AquaLab 1 test strips)
at weekly 20% water changes I dose ~1/8tsp KNO3
6 flourish tabs inserted in substrate about every 4 months

Fish: 6ish congos, 3 rainbows, 3 assorted tetras, 1 SAE, 1 3.5" rubber 
pleco, there may be some ghost shrimp left (congos ate most of them), 1 
khuli loach, snails

Plants: C. wendtii, hornwort, Bacopa monnieri, Ludwigia repens, java fern, 
Anubias nana and Rotala indica.

The Ludwigia, Rotala, and hornwort are growing wonderfully.  I have to trim 
the Ludwigia and Rotala weekly and replant the tops or I'd have plants 
growing out of my tank.  The crypts are doing okay but once in awhile the 
bottom leaves melt away even while new leaves grow out of the middle.  The 
bacopa grows extremely slowly.  Fortunately my tank is currently w/o any 
algal problems.

My concern is the new growth of the java fern and anubias.  Both put out 
new growth on a regular basis, but the old growth, even leaves just a week 
old, will start to look patchy.  I've tied both plants to driftwood, but 
even two months ago when they were on the substrate this would 
happen.  Fish do not seem to be the culprit.  It looks like the flesh of 
the leaf wears away leaving the gridwork behind.  These worn leaves to not 
fall off but continue to grow; the java fern leaves eventually turn black 
but stay on the plant.  The anubias leaves have lasted several months 
before I cut them off.

I considered the possibility that the pleco was rasping the anubias leaves, 
but that doesn't explain the java fern.  Could snails be to blame, and if 
so, any ideas on plant-friendly snail-eating fish?  The khuli loach used to 
keep them under control but has found another source of food.  If anyone 
has any suggestions, I'd greatly appreciate it.


Laura