On the java fern, cut the dead/dying leaf at the very base of the stem (near the rhizome). This is very healthy for the plant as it no longer has to waste energy repairing/using a damaged piece. It will also usually stimulate additional growth. The only time on a java fern I wouldn't cut off a damaged leaf is when there are very few (under 3 for example). This might put too much stress on the plant and slow its growth a lot.
Short story:
I purchased 3 very small java ferns from my local fish store and they were all not in great shape (stupid beginning plant person
). As I tried to nurse them back to health I trimmed off some of the bad leaves, but kept a couple that I would have normally taken off due to the small amount of leaves present. These damaged leaves continued to grow (albeit an eyesore), but they also produced new plants at the tips and midway up the leaves. Had I just cut all of these off I wouldn't have had the extra 5-6 plants that have now grown into medium size. I'm a huge fan of java fern, and even though I now have enough light to grow all but the most demanding plants, for ease of care, general beauty, I don't see anything beating it.
I'm actually thinking of removing most of my other species of plants (probably 6-7 others) and having an almost exclusive java fern tank (with the addition of some floating safe-house plant for fry and ground cover plant). It would certaintly curb my weekly hour pruning (mainly due to the wisteria which grows I swear 10-20% per DAY).
justin
EDIT: The plant with the dying leaves, how is the java fern planted? You need to make sure the rhizome (dark colored thick root looking thing) is exposed to the surface. While most of the "roots" on the java fern are only used to anchor the plant, I still prefer to keep them above ground, just weighing them down with a small stone or other decoration so that they can absorb all the nutrients they need.