There are lots of bacteria in your fish tank. And, for the most part, this bacteria goes a long way in stabilizing water parameters and ensuring your underwater environment thrives. Unfortunately, some fish can develop low immune systems in response to stress, and the bacteria can cause fin rot, an infection that can cause frayed fins, problems swimming, and eventual death if not addressed. You can avoid fin rot by ensuring that your aquarium remains healthy and balanced.
1. Stress and Bacteria Cause Fin Rot
As noted, most of the bacteria in your fish tank are harmless and play a critical role in keeping the water parameters stable. However, bacteria can also affect the immune systems of fish which may be weakened as a stress response. Stress in pet fish can result from:
- Overcrowding. Generally, each fish needs about one gallon of water for every inch of its body. So, a three-inch betta fish would need at least a three-gallon tank.
- Bullying. Fish can bully others when there’s not enough food or simply from being territorial.
- Poor diet. The Spruce Pets notes that fish food starts losing nutritional value from the moment it’s opened. Ensure that your fish get a balanced diet that corresponds with their species. Some fish like insects and worms; others enjoy leafy greens.
A fish may also develop stress in response to unbalanced water chemistry. Excess ammonia, for example, could cause burns and discomfort that lead to fin rot. Improper pH, excessive salinity, or acidity levels could also impact your fish’s quality of life.
2. Fin Rot Has Clear Symptoms
Understanding the symptoms of fin rot goes a long way in ensuring that your aquarium remains healthy and balanced. Symptoms of this condition include:
- Loss of appetite
- Lethargy
- Lack of movement
- Frayed fins or tail
- Ragged fins or tail
- Redness around the tail or fins
- Spots on different parts of the body
Over time, fin rot can affect a fish’s ability to swim, feed itself, and interact with others. Opportunistic fish may even view a sick tankmate as an easy meal and attack its tail and fins, leading to further stress. Petco notes that fin rot is contagious. While you identify the cause of your fish’s stress, place them in a separate tank so they can heal free from attacks from tankmates.
3. Fin Rot Typically Affects Long-finned Fish
Fin rot can affect any fish, regardless of whether it lives in saltwater or freshwater. Yet, this condition is commonly seen in long-finned fish, such as betta fish, goldfish, and angelfish. It can also be seen in koi. It’s worth noting that not only are some of these fish long-finned, but they can also easily outgrow their fish tanks. Many experts will recommend up to 250 gallons for a single koi because of how large they can become. Overcrowded fish tanks can cause stress, which can then cause fin rot.
Researching the types of fish you want to keep is critical when setting up an aquarium. Be sure to understand your tank’s size, gallon requirements, and fish’s dietary habits to provide a proper habitat.
4. Keeping Your Fish Tank Clean Is Key
Dirty or cloudy aquariums are among the chief stressors for pet fish. You can ensure that your aquarium remains a safe, inhabitable environment by:
- Ensuring you have an adequate filter. A strong filtration system is key to removing debris from the water, providing oxygen for the fish, and promoting good water quality. The filter’s gallons per minute should correlate with the tank’s size.
- Monitoring for excess algae growth. Algae blooms can deprive a fish tank (and its inhabitants) of oxygen. Overfeeding, improper filters, and overpopulation can cause dangerous algae blooms.
- Being aware of how much your fish eat. As a solid rule of thumb, if there’s still food left over five minutes after feeding your fish, you need to cut back on their portions. Overfeeding not only contributes to fish obesity, but the decaying uneaten food can cause unbalanced water parameters.
A note: cleaning your aquarium should not involve removing and replacing substrate. Your tank’s substrate has bacteria that help maintain the fish and keep the aquarium cycled. Removing the sand or gravel could throw off the water chemistry and cause further stress to your fish.
5. Quarantining Sick Fish Could Save Them
As noted, fin rot is a result of stress suppressing the immune system’s response to infections and bacteria. If you notice fin rot in one of your fish, quarantine them in a small back-up tank that has an adequate filter. During this period of isolation, monitor their symptoms and see if there’s any improvement. A fish that is stressed because of overcrowding may see its symptoms improve when separated from its tankmates. In another scenario, a fish that doesn’t get adequately fed because of competition could get proper nutrition when isolated, causing the fin rot to resolve.
If your fish does not improve in isolation, you still have options. Test the water parameters using a kit and see whether hard water (water with high levels of calcium and magnesium) is affecting your fish. You may also consider whether the type of fish you purchased is compatible with your aquarium set-up. For example, brackish fish (meaning those that need a mix of both salt and freshwater) need very specific water parameters. These fish include puffers, archerfish, and some gobies. You may need a specially formulated water mixture to ensure your fish thrive and avoid common diseases.
