Symptoms: white wavy worm-like parasites attached to the glass in the aquarium that tend to sway back and forth with the water circulation in the aquarium. Often, the fish do not seem to be affected at this stage. Given time for this disease to spread, the infestations usually begin on the fins, which usually become frayed and ragged. The disease will spread to the skin, eventually causing ulcerations and irregular areas of epidermal loss. Aeromonas hydrophila is commonly present in advanced lesions and contributes to the pathology. In the gills, Flexibacter Columnaris will color them light to dark brown and you will also notice some necrosis. On the skin, the fish will appear to have mold growing on it, with a slight cottony look, due to a fungal infection that has attacked the lesions and ulcerations. The lesions and ulcerations in advanced stages are usually infected with a secondary motile aeromonad. So as you can see, here is a situation where you have multiple infections present.
Cause:
Columnaris is opportunistic and strikes when a fish is stressed. Poor water quality, sudden changes in conditions, wide temperature swings, high nitrate concentrations, low dissolved oxygen concentration, crowding, shipping, and bullying can also trigger columnaris. Columnaris will be more virulent in temperatures above 77 degrees. My LFS tells me that summertime is "prime time" for this disease and they almost always suffer significant losses when fish are shipped in warmer weather. Hard water with a high Ph seems to accelerate the course.
Under appropriate conditions columnaris can spread rapidly and cause catastrophic losses. One strain has a virulence that is low and it takes a few days to kill the fish. On the other hand, the highly virulent strain will kill a fish in under 24 hours. If your fish has the highly virulent strain, there is not much that you can do to stop it or treat it. These fish often die so quickly that there may not even be enough time for them to show any external signs of infection.
Treatment: Treatment: First, slowly lower the temperature in the tank to 75 or 76 to slow the course of the disease. Also, since columnaris thrives in low oxygen conditions, the addition of an airstone or lowering the water level to create more splash from the filter will also help.
The most effective treatment for columnaris if the fish is still eating is medicated food containing oxytetracycline. Aquatronics makes such a food, as does Zeigler. Often, however, the fish is not eating by the time symptoms are noticed. Antibiotics in the water would be the next treatment option. Erythromycin (Maracyn), nitrofurazone, nifurpirinol, acriflavine, chloramphenicol or tetracycline can be used to treat the columnaris itself. However, a fish infected with columnaris often falls prey to a secondary infection which is resistant to both of these. Therefore, a combination of Maracyn and Maracyn Two or tetracycling and kanamycin is recommended. CONTINUE TREATMENT FOR A MINIMUM OF 10 DAYS.
I should note here that resistant strains of columnaris are cropping up on both sides of the Atlantic. We currently have nothing that will treat it. Strict quarantine measures should be maintained with ALL new fish. It's hard enough to lose a new fish, but to lose old friends is somehow worse.
I have also read that any Sulfa drug combination will work well. TMP Sulfa, Sulfa 4 TMP, or Triple Sulfa.
