Infection (Finrot) with clown loaches

[spulberica]

Hello,

I dare post given to my heart aching problem. Three of my five clowns are suffering from a bacterial infection, I think, that is looking like finrot. This is the result of nobody caring for my tank for 3 weeks except food.
One of them has lost 2/3 of his dorsal fin and has spots allover his tiny body.
I have started a tetracycline hydrochloride treatment (75' bath in 500mg per 5 liters of water) with all of them and 1/3 water change every day, but the infection in the one with the dorsal fin affected seems to have spread. One good thing is that he started to move his fin since I've started the treatment but the lesions are more obvious and have spread even more. There is no change with the others.
Could I be treating them wrong and if that's the case, what treatment should I apply?

[Diana]

Hi spuberica, welcome to Loaches!

Fin rot can be triggered by high nitrates, so doing some extra water changes, including vacuuming the substrate would really help.

Fin rot is often bacterial in origin, usually gram-negative. There are several bacteria that can cause it. A wide acting antibiotic usually helps, along with the improved conditions with the water changes.

The white spots.. are they patches of infection, or are they Ich? An external parasite?

Flavobacteria columnaris will show up as patches that may look white or pale grey. This bacteria can also cause fin rot. This bacteria responds to many medicines that treat gram-negative bacteria.

Often medicines are combined, for example a gram-negative antibiotic with one that treats gram-positive bacteria in case other species of bacteria try to move in on the stressed fish.

Here is a chart of fin problems, and medicines. If you click on the name of the medicine the product will show up with a list of what it treats. I do not see based on site info that tetracycline treats Flavobacteria columnaris, however Mardel Maracyn TC is Tetracycline and is specifically labeled for fin rot (second link).

http://www.nationalfishpharm.com/fish_d ... /fins.html

http://www.drsfostersmith.com/product/p ... atid=14713