Angelfish breeding... mold on fins

Question
Hello,
 I've got a 30gal tank with two plecos and 3 6mo old Angelfish (freshwater).  There's a tank divider cause two of the 3 are breeding.  I've got a whisper filter capable of filtering a 60 gal tank.  Ammonia is essentially zero, ph between 7-7.4 (my fish were bred initially in this water, and are not stressed by the high ph)  I do water changes about once a week, I remove 2gal, add 2gal, repeat 5-6x. Never really had a problem.  Even got the fish breeding, so I figured my water conditions were good.  Water here's pretty hard.  Sometimes I put a "softener pillow" in the filter.

Have a second 20gal tank with a 2nd pair of angelfish, no tankmates.  Both tanks have the same problems.  Maybe the contamination came from the buckets I use to do water changes.

Anyway.  Shortly after the eggs became "wigglers" I noticed a cottony/spiderwebby fuzz on the bottom of the anal fin of the female, and the ends of the stabilizer fins.  This appears only places that seem to drag on the bottom.  Right now I've got all the gravel out so the fry don't get stuck... and I vacuum  regularly.

There's also spiderweb-like pieces that float on the top of the tank, and around on the inside.  I just pulled a piece out that was floating... and outside the water it looks like a fine, silky thread which will break into pieces if pulled, does not stretch... not mucoid.

The fry are just about free swimming, aren't moldy, aren't dying really.  The fish don't seem distressed. They're busy with the fry.

None of the descriptions of fish diseases I've found seem to fit.  I'm probably going to wait a while to see if it gets worse, it has been there already for 3-5 days, and doesn't seem to be progressing.  If there's some way to treat this, will it harm the young fish?  (obviously saving the breeding pair is more important)

I'm treating the 20gal already with jungle fungus clear... (nitrofurazone, furazolidone, potassium dichromate)

Will the antibiotics kill the fry?
Will this get rid of the spiderwebs?


Answer
Hi Benihanna;

It sounds like there was some injury or irritation to the fins and it then became open to infection by saprolegnia. It is indeed a fungus. If it's been floating around in the tank there is or was some area somewhere that became infected with it. Saprolegnia feeds on decaying organic matter. It may have been decaying eggs, decaying food or decaying waste. I don't think the fungus clear will hurt your fry. I don't think it's all that effective against this fungus either though. Here is a good article about saprolegnia that includes photos and treatment options;

http://tinyurl.com/2luc94

I hope they do okay...

At Your Service;
Chris Robbins