anibis
Aquarium Advice Activist
Tetracycline is most effective for gram positive bacteria, columnaris is gram negative. Nitrofurazone (Furan-2), Kanamycin (Kanaplex), or Minocycline (Maracyn-2) are better options. Triple sulfa can be hit or miss, works best if used early on.
Another note, gram positive antibiotics (like Tetracycline) are more likely to upset your beneficial bacteria than gram negative.
If tetracycline is all you can find then try it, if the fish don't show any sign of improvement after a few days then discontinue use. It is MOST effective against gram positive, but it may have an effect on gram negative.
I'd test your water daily while dosing any antibiotic just to be sure.
Another note, gram positive antibiotics (like Tetracycline) are more likely to upset your beneficial bacteria than gram negative.
If tetracycline is all you can find then try it, if the fish don't show any sign of improvement after a few days then discontinue use. It is MOST effective against gram positive, but it may have an effect on gram negative.
I'd test your water daily while dosing any antibiotic just to be sure.