Minnow (phoxinus Phoxinus) Disease

Hello, I have about 80 minnows (Phoxinus phoxinus) which I caught 3 weeks ago, in a 260L. A few of them has gotten gray backs. Which disease is this?

 

If you caught those in wild yourself those can carry some serious unknown disease or parasites.. where are you from..

 

Yes they are from the wild. I put them through prazI and antibiotics treatment to be safe but I know that it won't kill all parasites etc out there. I'm from sweden

Edit: Looks like it's Columnaris to me. I have doxycycline (broad spectrum) but only 200mg. Would it be enough to treat 260L?

 

So this was my exact train of thought on how to offer my extreme knowledge on your predicament...

"I'm going to google 'columnaris'.
Wait, no, 'columnaris in minnows'.
Wait, no, 'columnaris in Swedish minnows'.
Swedish Fish.
I like candy."

Swedish Fish are seriously one of my favorite types of candy. Also, I didn't google about the minnows but are you planning on keeping them as pets with other fish or just on their own?

 

Haha Swedish Fish are not so bad..

I'm planning to keep them with my 4 dwarf gouramis, 2 bristlenoses and 5 SAE's.

So what do you think? Could it be columnaris?

 

Haha Swedish Fish are not so bad..

I'm planning to keep them with my 4 dwarf gouramis, 2 bristlenoses and 5 SAE's.

So what do you think? Could it be columnaris?

Here is an incredibly detailed veterinary research report with pictures of dead fish with the disease. I would suggest looking at this rather than asking someone who doesn't know anything about it. It is very informative.

 

They are not sick they are probably PH shock because the rain water is netural ph 6.0 and your water is probably alkaline around 7 or 7.5
Systemic bacterial infections can be helped with a doxycycline (I use it myself) but the main thing to remember is correct the root cause of the problem.

 

Today I noticed one of my SAEs and one swordtail has a few small white lesions around the top fin. The swordtail also has something which looks like a small fin rot.

The tank is a 260L which have been running for longer than a year. Using co2 so ph is usually 6.8. KH 4.5 GH 7d Nitrate 20 Nitrite 0

Would antibiotics medicated flakes treat externally as well or only internal? I have also ordered esha 2000 which will arrive tomorrow.

 

Yes the medicated flakes will treat the external part because its systemic and runs thru the blood. The fishes own immune system and water changes will clear up the fungus decayed fins.