My tank crashed.

Hi, I'm a new subscriber, with two freshwater planted tanks, one of which 
has been running for nearly 3 years, the other (higher tech) just over one 

Here's what's going on:  The plants in my 38 gallon tank that I've had
running for nearly 3 years died over a 5 day period. 

Specs:  38 gallons
	75 degrees
	7.5 Ph
	~350 ppm hardness.
	Low-tech tank:  River gravel substrate
	2 30 watt flourecents tubes badly in need of replacing.
	Tetra plant fertilizer (forget the name of it)

12 Australian Rainbows and 1 Striped Raphael Catfish.  The tank was 
heavily planted with Jungle valisneria, one HUGH beautiful Java Fern, and 
small asorted echinodorus species

What happened was this:  2 weeks ago, two of my Rainbows developed what 
looked like bacterial body slime, so I treated the tank with an 
anti-biotic called Furacyn.  I treated for five days (1 dose every other 
day) then waited thee days and repeated the cycle.  I had removed the 
carbon the filters (two whisper power filters).  Two days after I 
completed the second round of treatment (the fish seemed well on their 
way to recovery), I noticed that the jungle valisneria was turning 
yellow, as was the java fern, which had developed holes in the leaves.  I 
added the carbon back into the filters.  That was two days ago.  I 
planned to do a large water change this weekend.

Well, the plants continued to deteriorate.  The sword plants seemed for 
the most part unaffected.  They hadn't been doing all that well anyway, 
because they weren't receiving enough light (blocked by the other plants) 
But they may be the only plants to survive.

This morning, as I was getting ready for work, I noticed that the 
valisneria was collapsing back on itself instead of floating on the 
surface, and looked yellow and somewhat transparant.  I also caught a 
wiff of the tank.  It reeked of rotting plants.  

Fearing an ammonia spike (I haven't had a chance to test the water) I 
immediately netted all the fish and transferred them to the 110 gallon.  
The fish did not at all seem in distress before moving them.  I then 
ripped out all dead plants, and left in all the ones that seemed like 
they might make it (I really hope the java fern can recover--it was huge 
and beautiful and healthy only 2 weeks ago)

I *am* going to set up a quarantine tank as soon as I move into a bigger 
place (this may). I should have done it a long time ago.  *sigh*.

Anyway, anyone have any ideas what happened?  The Furacyn does NOT 
mention that it's bad for plants.  Has anyone had this happen to them?  I 
thought there might be a possibility that since it's a low-tech tank 
that's been running for 3 years, that it might have just been no longer 
able to sustain itself.  But I suspect that if that had been the case, 
the deterioration would have been more gradual, not over the course of a 

Thanks for your help.

Cathy Byland