Plants help fish slime coat?

Steve wrote:
> A tank heavily planted is extremely good for fish and (I read) provides
> protection against diseases, encourages the protective slime coating on 
> fish in addition to oxygen and food!  The SECRET to raising up a batch 
> of fat and healthy fry is to have LOTS of floating plants which provide 
> free homes and food for infusoria in your tank.

I must agree with this--I've really noticed how amazing the change is:
the fish really perk up in a tank with live plants (even beyond that which
O2 would explain:  I have very light bio-loads).  Even in a tetra-only tank,
many of my tetras are constantly "hanging around" the live plants, at
the discrimination of the plastic plants.  After introducing live floating 
plants, many of my fish that had spent ALL their time in the bottom 1/3 
of the tank now spend ALL their time at the water surface, just under a 
leaf or clump of vegetation.  I was shocked!  (A really good example is 
my emperor tetras [Nematobrycon palmeri] or my female Betta splendens at 
work.)  They really seem to desire exploration through a jungle of 
vegetation ...even when it appears they are not foraging.

I didn't realize plants encourage slime coat production or protect against
diseases, though.  I wonder if that is merely a result of lower environmental
stress?  I'm trying to figure out the biological component...

Some of my fish seem to really enjoy "rubbing" through live plants, though.
(No, we don't have ick!  :-)  Do you think this may have something to do
with slime coat production?  It seems to almost be a method of grooming
or self-cleaning, like many mammals exhibit.  I don't see this behavior
with the plastic plants in the same or different tanks.

Any additional notes on unique fauna behavior in planted aquaria?

charleyb at gr_hp.com	or	charley at agrostis_nrel.colostate.edu