Columnaris Symptoms and Treatments: What is it? Columnaris is a gram negative aerobic bacterial fish disease. This means that it thrives in well oxygenated, often very "clean" tanks unlike some other diseases that thrive in low O2 and high organic loads. It is caused by the bacteria flavobacterium which is a common bacteria found in all fish tanks and is not a problem until new fish are introduced to the tank carrying the disease or a fish is weakened or injured allowing the bacteria to take a foot hold. Once it becomes a disease on your fish it will spread rapidly through the aquarium. It also thrives and reproduces faster in warmer tanks over 80 degrees but can still exist in a 78 degree tank and lower though the bacteria will not reproduce as fast as the temperature is lowered. Identification: It can be confusing and hard to identify initially as there are four known strains of the disease itself. In the slower moving strains there will be visible symptoms. The disease in the past has been called Saddleback Disease because often the afflicted fish will show a pale saddle like area across their dorsal fin onto their back. Or it has been called Cottonwool or Cottonmouth disease because the fish will show cottony tufts on their fins, scales and often on their mouth. You will usually see these two symptoms on the slower moving strains. With the faster moving strains there will sometimes be virtually no symptoms. One day the fish will be fine, the next day dead. As I've had this go through my tank twice now in the last year there are some symptoms to watch for with these strains. The fish might be off by itself a little, then you may see it going up for air or gasping at the top, there may be paleness and/or bloating around the pectoral or ventral fin area, the fish may appear as if it is swimming erratically like something is going on with its swim bladder, it may or may not pinecone with scales sticking out, finally it will be on the bottom of the tank and death will follow rapidly. This can all happen within 12-48 hours. The bacteria will attack the gill tissue which is why the fish will be gasping for air in the tank, breathing heavily, or at the surface of the water, once its in the blood stream, death occurs very fast. As a side note, these latter symptoms can also be caused by iridovirus found in gourami's, bettas and other species of fish. Prevention: The most important thing you can do to prevent this disease is by a quarantine of ALL new fish. I am as guilty of not doing this as others at times and the times I have not done the proper quarantine I have brought this disease into my aquarium with disastrous results. A two-three week quarantine is a must where any symptoms will show up and can be treated for appropriately. It is important to have adequate minerals in your tank as well with general hardness not being too low. Please see the following article: Important: - Understanding pH, KH, GH in Home Aqauriums Avoid overstocking or aggression in your tank as the stressors will also lead to weaker fish. Treatment: Lower your tank temperature to 75 to help slow down the spread of the disease. The best treatment if you're in the US is a combo antibiotic treatment of Kanaplex and a nitrofurazone based medicine found in the following popular brands: API Furan-2 or Tetra Fungus Guard or Jungle Fungus Clear tabs. If you can't get a hold of Kanaplex then Mardel Maracyn - 2 (minocycline) is your next good option. You'll want to remove carbon during treatment. Follow the dosing on the packaging and do at least two rounds of nitrofurazone with a large water change in between. Its best to do one round of Kanaplex as its a strong medicine and can be hard on the kidneys if treated for too long. According to Seachem a second round can be repeated if necessary though. Medicated kanamycin fish flakes are another option though not necessary for successful treatment. If its in your tank then best to go ahead and treat the whole aquarium even if only some fish are exhibiting symptoms. Once treatment is started you may continue to see deaths of already infected fish for another 24-48 hours but after that they should stop. I had a betta fish exhibiting symptoms like the gasping for air and she was saved in time by the medicine. I don't know the long term effects of the gill damage once treated. Nitrofurazone is invert safe. It will turn your tank a "lovely" shade of yellow but it works well. Kanaplex says to remove inverts though I have personally never had an issue treating with this combination and I have Cherry and Amano shrimp and nerite snails in my tank. I guess its a "use it at your own risk" but wanted to share my own experience. In general these two medicines will not negatively effect your nitrogen cycle. If you have a very new or immature cycle it probably could cause a cycle bump but again I have never personally had an issue with these medicines that are considered safe for the bio-filter. Sometimes I see Erthyromycin or Tetracycline or Oxytetracycline mentioned as treatment. None of these treatments will work as they are primarily for gram positive bacteria and will be useless for this disease. If you are not in the US and cannot get a hold of the antibiotics mentioned above then aquarium salt has been shown to be a positive treatment method and may be your only way of stopping the disease. I think Amazon UK does have Tetra Fungus Guard though last time I checked. Salt Treatment: types: you can use aquarium salt, or any un-iodized salt such as Kosher Salt, Sea salt, Canning and Pickling Salt. Add in 1 tsp per (actual) gallon of water, dissolved first in some tank water before adding it to the tank. 12 hours later repeat this dosage and finally 12 hours after that a final dosage. You will now be at .3% salt level which is effective for eradicating the bacteria and is the same dosage recommended for ich treatment when treating with salt. The vast majority of fish can handle this amount of salt for a two week period. Some fish of course cannot and may need to be removed during treatment, though even scaleless fish can handle 2 tsp per gallon for short duration periods. Salt does not evaporate and must be replaced with water changes, i.e., 5g of water out, 15tsp or 5 tbsp salt back in. Thanks, hope that helps anyone looking to treat this terrible disease.