Please Help Me!

[gtexan02]

About 4 days ago, 2 of my fish suddenly died.

One was a cardinal tetra who lost half of its blue coloration along the back of the body, along with almost the entire caudal fin. It was dead within hours.

The other was a German ram, who had no visible signs except for a slight whitening around the mouth. It died within 2 hours.

I also had 2 angelfish, one of which developed very frayed and rotting fins, and both were returned to the LFS (the larger was bullying some of the other fish and causing unneeded stress).

My current stock is:
2 German Rams
4 Cardinal Tetras
6 Corydoras
1 Bristlenose pleco

About 3 days ago, I noticed one of the corydoras had a white sphere-ish shaped growth on the very tip of its dorsal fin. I started treating with melafix, assuming it was some sort of fin rot or something residual from the past outbreak (which I assume was colunaris). 3 days have gone by, and the white spot looks as bad, if not worse, than it did before. The fish is still schooling/eating/swimming perfectly healthily. The thing that worries me is that I noticed the same whitish grown on the tailfin of my bristlenose. Its whitish and a bit "gooey" looking, not really a sphere, and definitely on the fin (not the body).

What should I do? Should I contine treating with melafix? Should I start also treating with pimafix? I don't have a quarantine/hospital tank, nor the means to really establish one right now. Should I treat with something stronger? (Maracy-2 or tetracycline?), or will this kill off my biological filter? Thanks!

By the way:
Tank size - 55 US gallons
Cycled using fishless cycle
Temperature was 78F, recently lowered to 74F
Filtration - Fluval 304
Weekly 30% water changes
Readings as of this morning:
Ammonia - 0ppm
Nitrites - 0ppm
Nitrates - <5ppm
pH - 6.5
KH - 2 degrees

First signs of disease occurred the morning after I brought home the 5 cardinal tetras, 1 german ram, and the birstlenose

 

[WILDER]

You have columnaris and secondary bacterial inffections with the finrot, you need a strong med like maracyn one and two, tetracycline is very good but it will wipe your bacteria colony out in the filter.

 

[gtexan02]

You have columnaris and secondary bacterial inffections with the finrot, you need a strong med like maracyn one and two, tetracycline is very good but it will wipe your bacteria colony out in the filter.

I've checked a lot of online posts, and the reason I am doubting columnaris now, is multireasoned:
1) The white lesion does not look "fuzzy" or like a fungus
2) It is affecting the dorsal fin only, not the body
3) The fish is acting normal after having been "infected" for 3 days. The other two that died did so instantly


I've looked at a lot of pictures, and it seems to me the most likely cause is "lymphocystis" Is this possible/probably? What should I do? I am afraid to treat with maracyn-2 if its a viral infection, as this will risk disturbing everything else in the tank. Thanks

 

[WILDER]

lymphocystis looks like a cluster of berries on the fish or a cauliflower, still need a bacterial med for the fins, but it dosnt sound like lymphocystis to me if there no growths on the fin

http/www.aquarticles.com/articles/manage...mphocystis.html

White around the mouth is columnaris you still have a bad bacteria infection i would get treating with the maracyn one and two, here a link to finrot.
http/petfish.net/kb/entry/31/335/

 

[gtexan02]

lymphocystis looks like a cluster of berries on the fish or a cauliflower, still need a bacterial med for the fins, but it dosnt sound like lymphocystis to me if there no growths on the fin

http/www.aquarticles.com/articles/manage...mphocystis.html

White around the mouth is columnaris you still have a bad bacteria infection i would get treating with the maracyn one and two, here a link to finrot.
http/petfish.net/kb/entry/31/335/

Should I treat with both at the same time, or one and then the other? How long is the recommended treatment period? Thanks

 

[black angel]

your kh is really low and ph crashes can cause greyness and mucus on fish. You need to add something like coral gravel to raise the kh so raising the ph.

 

[WILDER]

I would suggest doing what black angel has said, crap at kh, then add the med, good luck.