Treating Fin Rot--Do I need a hospital tank??

[rsi77]

Hello,
I have a 46g tank with 3 catfish (something similar to Pictus, but with stripes), 3 greenhump catfish, 5 Red Minor Tetras, 2 Dojo loaches and 1 tiger botia. I noticed that the two newly obtained dojo's have signs of tail rot. The greenhumps also seem to, but to a lesser degree. I plan to treat with Maracyn 1 & 2. I used it in my smaller tank with a couple glass catfish and they're doing very well now. My question is, why would it be advantageous to use a hospital tank if there's a good chance all of my fish may need the treatment. Assuming that the stuff is contagious it seems to me that I'd be better off treating all of the fish, rather than just the ones who have visible signs of a problem.
I've checked my nitrate (<20), nitrite (0), Ammonia (0) and all seems to be in good shape. I've also done regular water changes. But the tank is relatively new--about 3 months.
Thanks for any advice.
Ron

[Marc van Arc]

Assuming that the stuff is contagious it seems to me that I'd be better off treating all of the fish, rather than just the ones who have visible signs of a problem.

If it's bacterial fin rot it IS contagious, so you should treat all fish.
The hospital or quarantine tank was invented to avoid the above mentioned step

[MatsP]

Be prepared for a cycling of the tank, since most of the antibacterial treatments also kill of the beneficial bacteria in the filter/substate...

As Marc pointed out, the idea of quarantine is there to avoid the sick fish getting into the tank with the healthy ones in the first place.

--
Mats

[rahendricks]

Acording to the directions on the Maracyns, they will not affect biological filters when used as directed. I'm not sure I completely believe that but, I have had to use them on two occasions with mature tanks. I had suspected some of the healthy fish were carriers or developed an immunity to something present in the tanks. New, healthy fish (that had been in quaruntine for weeks) got sick within days of being added to the tanks but the existing fish never showed any signs of ailment. Anyway, I didn't find any spike in ammonia, nitrite, or nitrate during the course of treatment. I do have heavily planted tanks so its possible that any spikes were absorbed by the plants. You should probably check the ammonia, nitrite, and nitrate daily and be prepared to do a water change if you see a spike. I use antibiotics as a last resort but the Maracyns do seem to be fairly safe.