Well, it looks like my tropical fish are sick again! I brought in a pictus catfish and some new guppies and I think they spread something to my fish. The tank is 20 gallon, temperature 75°C, Ph 7.0, ammonia 0, nitrite 0, and I don't have a nitrate kit. The tank has 1 common pleco, 1 peppered coryda, 1 lyretail balloon molly, 1 neon tetra, 2 glowlight tetras, 1 whitecloud, 6 guppies, and 4 or 5 guppy fry.

Over the weekend I lost two guppies and the others guppies have been displaying some weird symptoms. They have been flashing against the rocks and the two that died had fuzzy white patches on their backs. Immediately I figured fungus so I started dosing with Jungle Fungus eliminator and Melafix. Over the past two days the fungus hasn't subsided and the tailfins are getting ragged. The ragged edges aren't white like tail rot, it just looks like someone cut them clean with a pair of scissors.

The fact that the fish are flashing and the fungus meds aren't working is starting to make me wonder if it is some kind of parasite. Is there any kind of parasite out there that could cause these fuzzy patches and ragged fins? I've already battled ich with the glowlight tetras and molly months ago, but it just looked like grains of salt. I'm so confused. Right now I've removed the other meds and I'm treating with coppersafe.

Just lost another guppy 2 minutes ago. I added extra aquarium salt and I'm slowly upping the temperature. I also dipped some of their food in Aquarium Products General Cure for internal parasites. Another male guppy seems to be on his way out. He has ragged fins and he's very listless. My favorite guppy as well:( The guppies seem to be the only ones dying off.

Could be coulmnaris, which often looks like a fungus but isn't. You need to get an anti-bacterial med, what is available to you depends on your location. If you are in the US or Canada, Maracyn & Maracyn II by Mardel should do the trick.

It makes sense to me. After doing research I figured that it was maybe some advanced case of ich and started raising the temp. Since raising the temp, I lost an additional 3 fish, so obviously if it was columnaris I was speeding up progression of the disease. That makes the death toll 5 guppies now in 3 days. So far it seems to have only attacked the guppies. Worst part though is I have no quarantine tank, and it will take a week for the maracyn to be shipped. I have to buy all my meds online since there's only Walmart here which doesn't carry anything useful. So right now there's coppersafe still in the tank and some extra salt. I do have melafix, so is it alright to add both to the water as a last resort till the meds arrive?

I just ordered the meds, which should arrive in a week. Just to be safe, I ordered Maracyn 1 and 2 8 tablets, Furan 2 capsules, and Tetracycline capsules, and Jungle Net Soak. Which is the best for treating columnaris?

Tetracycline >> you can buy this with out a doctor's note!! That's antibiotic nuclear warfare lol.

Remember that antibiotics will more than likely kill all bacteria including that which processes waste in your filter, ie the beneficial kind.