Fungal disease in fish (columnaris) is a bacterial infection disease that appears as a white layer on the fish’s mouth or body.
The initial symptoms include a change in the structure of the affected area and a fungus-like appearance. If not treated, the fish fungal disease can lead to the death of the fish.
The disease, which has lesions resembling mold, can be treated with basic aquarium care and various antibiotics.
What is Fish Fungal Disease (Columnaris)?
Fish fungal disease is an infectious disease caused by bacteria colonizing a part of the fish. Proper diagnosis should be made by identifying the symptoms and applying the correct treatment.
Guppy Fungal Disease Treatment
Columnaris is more common in live-bearing species. This bacterial disease is highly contagious. The fungal disease most often seen in guppies affects female guppies more. If not treated, you may lose all your fish.
After guppies, goldfish are also frequently affected by the fungal disease. The information and methods we provide here can be applied to all fish.
How to Prevent Fungal Disease?
Fish fungal disease can be prevented by regularly maintaining the basic aquarium care. As the disease is bacterial, the best practice is to change the water regularly and vacuum the gravel regularly with a gravel vacuum to prevent the increase of nitrite and ammonia levels.
Poor feeding of the fish will also make it vulnerable to the disease. Support its nutrition by using quality and appropriate feeds in the right doses. Maintaining good water quality can also prevent infectious diseases.
When you want to add a new fish, we strongly recommend using a quarantine aquarium to ensure that the fish is not diseased. This practice will protect the fish in the main aquarium if you have bought a sick fish.
For the quarantine and the main aquarium, you should not use tools like scoops, siphons, thermometers interchangeably between aquariums. If you cannot obtain a second set of tools, you must disinfect them before using them in another tank.
Symptoms of Fungal Disease in Fish
The initial symptoms of fish fungal disease are:
- Vague greyish patches on the fish’s head, gills, and fins
- A cotton-like, fungus-like appearance at the tip and edges of the mouth
- Frayed appearance in the tail and especially the fins
- Paleness in the general color of the fish
The majority of the symptoms of fish fungus can be seen on the external body. Grayish patches appear on the tail, fins, and head. As the disease progresses, these patches can turn from gray to brown or red. The fish loses its vibrant, bright appearance, and its color fades.
As the colonization of the bacteria increases, it takes on a cottony appearance, and eventually, the fish’s mouth or body structure deteriorates. As the infection progresses, the tail and fins become worn out and lose their form. As bacteria multiply, they also affect the fish’s gills, preventing it from getting enough oxygen.
As a result, the fish tries to get enough oxygen by breathing faster than normal. A fish suffering from this disease, if not treated, will stop swimming and moving entirely and become paralyzed.
Fungal Disease Treatment in Fish
Such infections should be treated with antibiotics and additives applied to the water. Use aquarium salt or rock salt to reduce stress in fish and weaken bacteria.
- Raise the water temperature to around 29-30 degrees Celsius.
- To treat fungal disease in fish, you can use Terramycin, a commonly used fish fungal medication. Add Terramycin to a certain amount of water taken from the aquarium and let the fish bathe in this water for a while.
- You can use aquarium salt to reduce stress and speed up the fish’s recovery. Change about 30-40% of the water and add one aquarium salt for every 20 liters. If you choose to use rock salt, a teaspoon for every 20 liters will suffice.
- Use Terramycin and aquarium salt regularly every day. Changing the water every other day will suffice.
Once the treatment is successful, change about 70% of the water to balance the temperature and salt in the water.
Why Does Fish Fungus Occur?
The bacteria causing fungal disease tend to target stressed fish, making the disease easier to contract. By preventing stress, you can largely prevent the disease.
- The following reasons will facilitate the bacteria:
- Constantly high water temperature
- Poor water quality
- Insufficient or wrong feeding
- Stress due to the transport of the fish
This bacterium can enter the fish’s body through tiny wounds or the mouth. Columnaris is a highly contagious disease. It can be transmitted through the tools you use, your hands, or even the feeds you give.
Always disinfect your tools and hands and keep them sterile. If you use multiple tools for several aquariums or use only one filter, it is likely that the bacteria will spread to other aquariums.