Fin rot is a common disease in angelfish. Once it takes hold, the bacteria will eat away at the tissue and work into the deeper layers. This will cause the angelfish’s tail and side fins to become ragged, torn, or rotten. If left untreated, the disease will eventually take over the fish’s entire body. It can also transmit to other fish in your tank, spreading the problem.
If your angelfish gets fin rot, the first step is to quarantine it. Place it in a tank of its own with decorations, and then thoroughly clean the original tank. Add aquarium salt to both tanks, in small amounts, and then use antibiotics. Maracyn, chloramphenicol, oxytetracycline, and tetracycline are available over-the-counter. If the infection worsens, a vet can trim away dead tissue and prescribe stronger medications.
If you want a natural solution, try using hydrogen peroxide or Melafix on the diseased angelfish. Keep in mind that this only works on fish that have mild cases of fin rot. If the severity of the disease escalates, the fish will be unable to regrow its fins and may die within a few weeks.
What Does Fin Rot Look Like On An Angelfish?
Fin rot has very clear signs that you can spot. Since this infection becomes more dangerous the longer it continues, that’s important.
- An angelfish with fin rot has discoloration around the edge of its fins
- This will escalate into a milky film around the affected areas
- The corners of the fin will begin to fray and tear
- Sections of the fin will start falling off
- This transition is gradual and can go unnoticed until your angelfish has shredded fins.
- Eventually, the fins will grow bloody, red, and inflamed.
- As the bacteria work into the deeper layers of the tissue, blood vessels will be damaged.
Throughout this, your angelfish’s immune system will try to combat the infection. However, since the edges of the fins are raw, they’re vulnerable to secondary infections. Fungal growths like Columnaris can develop. The infection may also spread to other areas of the body, manifesting as:
- Abdominal swelling
- Ulcers on its sides
- Lesions along its underside and back
This damage will be due to mycobacterial infections, according to Seminars in Avian and Exotic Pet Medicine. Not only will the bacteria itself open up wounds. The angelfish may rub against the tank’s wall or decorations to alleviate its discomfort. Sadly, this only causes more pain.
What Causes Fin Rot in Angelfish?
Fin rot is usually caused by bacteria. The most common types include:
- Vibrio bacteria
These can be introduced to the tank by an outside source, like a new fish. They can also grow inside the tank if the conditions are right. Let’s explore all the ways your angelfish might’ve gotten fin rot.
Low Water Quality
If you let the tank water get murky, chemically imbalanced, or thick with algae, this may encourage bacteria to grow. Unless you’re very experienced with aquariums, you should always invest in a high-quality filter.
Mechanical, chemical, and biological filtration will help sift through contaminants in the water and rebalance the tank. Every week, adjust at least 20-30%t of the water to keep nitrates at an appropriate level and eliminate other nasties from the tank.
In your aquarium, uneaten food will begin to decay, which can increase ammonia levels and nitrites. This chemical imbalance is where bacteria can thrive. Likewise, your angelfish will take a hit to their immune system, making it harder to fight off any illnesses like fin rot.
Fluctuating pH Balance And Temperatures
If temperatures are too hot or cold, your fish will become lethargic and weak. The shock to their system can lower their immune system, opening the door to bacteria.
For angelfish, try to keep your tank between 78 to 81 Fahrenheit degrees. Very low temperatures cause your fish to become stressed.
If you’ve just purchased a new batch of fish to fill the aquarium, you may have welcomed an infection into the group. All new fish should be quarantined to see if illnesses develop first. That way, you can treat the sickly angelfish by itself and keep the others safe.
Aside from that, the more fish you have, the easier it is for sickness to propagate. If one of your fish became infected by the bacteria, this will spread in the water to all the others. More fish will also result in more waste, which can unbalance the tank’s water quality.
Having colonies of bacteria and even fungi present in the water is common for an aquarium. Typically, a stable angelfish have no problem coexisting with these organisms. However, its immune system crashes when the fish is stressed, which allows the infection to run wild. Angelfish usually get stressed by:
- Too much light
- Too many males in the tank
- Too few hiding places
- A too-small tank
Angelfish Fin Rot Treatment
Fin rot will directly attack your angelfish’s tail and side fins. If it’s not properly handled, it can result in permanent damage to your fish’s body and even cause death.
There are ways to treat this disease. Antibiotics can be used in the aquarium to target and destroy the bacteria. The most common ones are:
These have no adverse effects, a very high success rate, and can be purchased over the counter.
How To Cure Fin Rot In Angelfish
With that said, you shouldn’t just pour a dose of antibiotics into your tank and call it a day. There are steps you need to take leading up to the antibiotics, and aftercare techniques you should apply afterward.
Severity of Fin Rot in Fish
Depending on how severe the fin rot is, you may need to apply a heavier or lighter dose of antibiotics. The treatment may also be necessary for a greater period of time or be paired with other remedies.
Mild Fin Rot:
- The tattering is moderate
- The fins are darker in color
- The redness is mild
- There are signs of irritation
Moderate Fin Rot:
- A large part of the fin is rotting and frayed
- The remaining part of the fin is decolorized and very black.
- There are signs of the fin completely dying
- Clumps of the fin slip off when the angelfish is touched or bumped
Severe Fin Rot:
- A large portion of the fin has rotted or fallen off
- The fins are bleeding and red
- There’s a great deal of inflammation
- The fins are covered in red spots
- The fins are short or nonexistent
- The fish is showing rot on other parts of its body
You should also look out for secondary bacterial or fungal infections. These will need to be treated separately and may not be covered by your fin rot medication. For example, a cotton-like growth or bloody patches on the angelfish’s body suggest new infections have developed.
Quarantine Your Sick Angelfish
The infection will quickly spread throughout your tank if allowed. Because of this, you should remove the diseased fish immediately. Place it in a new tank, all by itself.
Make sure that the water parameters are well balanced and that your fish has plenty of decorations. It will be stressed enough by this whole ordeal. Getting dropped in a bare tank will only make this worse.
Clean Your Fish Tank
You should now clean the original tank to try and limit how much bacteria your other fish are exposed to. Each day, change 5-10% of the water for a total of 3-6 days. If you change the water too quickly, this might shock the fish and cause them to grow ill anyhow.
You should treat the original tank with aquarium salt and keep an eye on any symptoms. If they appear, you will need to use antibiotics on the main tank as well.
Use Of Aquarium Salt
When measured correctly, aquarium salt will prevent the development of both bacteria and fungi. In your quarantine tank, use 1 tablespoon of aquarium salt for every 5 gallons of water. Blend it in a glass with the tank water before pouring it in, so that it’s properly dissolved.
For the quarantine tank, use antibiotics. You should follow the instructions on the label to see how much you need for your tank size, your fish, and the symptoms it’s displaying.
Most fin rot medications can be purchased at pharmacies or pet stores. If you’ve had repeated cases of fin rot, then it’s worth talking to a veterinarian about stronger medication.
Trim The Affected Fins
If the fin rot has gotten severe, the dead tissue might need to be removed. This should never be undertaken at home, unless you have training and experience in performing surgery on fish.
Instead, you can schedule an appointment with your veterinarian. An expert will be able to trim and clean the edges with antiseptic and sterile scissors, once they’ve sedated the fish.
How To Tell Fin Rot Is Getting Better
After 10 days, if treatment is successful, you’ll see the fish:
- Regaining its color
- Having more energy
- Healing from the physical damage
If your angels show any negative side effects from the medication, or doesn’t appear to recover, then contact your vet. Depending on how bad the fin rot is, it may take the angelfish several weeks to fully recover. It should not get worse, though.
How To Treat Fin Rot Naturally
Natural, at-home solutions won’t be effective against severe fin rot. However, if you catch the sickness early, you can apply milder treatments. This ensures you don’t overwhelm your angel (or your budget) with name-brand medications.
Maintain Cleanliness of The Tank
The cleaner your tank is, the less bacteria can thrive, and the less likely it is your angelfish will contract fin rot.
- Be sure to clean the tank often
- Change 20-30% of the water during each session
- Remove food if your angels don’t eat it within 2-3 minutes
- Make sure your filter is high quality and regularly cleaned
- Test the water to ensure that the pH level, ammonia, and nitrates are all in good balance
If your fish do contract fin rot, it’s possible their immune system can fight it off. This will only happen if they’re not also struggling with unclean water or fighting off extra bacteria. Keeping the tank clean will solve present issues and prevent future ones.
Treat With Aquarium Salt
Saltwater has antiseptic properties that can help treat minor fin rot. You can apply a small amount to your tank when you notice fin rot developing.
Of course, this should be approached cautiously. Saltwater angelfish need a particular amount of salt, while freshwater angelfish can be killed when introduced to too much salt. Only use aquarium salt that has been designed for medicinal purposes, and measure it carefully.
Apply Hydrogen Peroxide
If you’re an experienced fish keeper, you can try to treat your angel’s fin rot more directly. If you haven’t cared for or handled fish in the past, this may be too risky. Instead, you should rely on antibiotics or contact a vet.
- Catch the fish using a net or a plastic cup with no sharp edges
- Dip a cotton swab in hydrogen peroxide
- Dab it gently on the angel’s rotting fin
- Pat the fin dry.
- Return the fish to the tank no more than 30 seconds later
Your fish may get stressed if kept out of the water for long. Peroxide is not dangerous to angelfish, but can cause minor irritation.
You should never pour it into the tank or over your fish, as this will disrupt the chemical balance of the water. Instead, the minor amount you pat onto the fish’s wound will attack the bacteria without harming the fish.
Use A Natural Antibiotic
Melafix uses tea tree oil to kill bacteria and repair damage caused by fin rot. The positive thing about API Melafix is that it is safe and has no adverse effects, according to the Journal of Exotic Pet Medicine. The College of Veterinary Medicine assessed Melafix and found out that doesn’t:
- Impact biological filters
- Cause water discoloration
- Change the pH balance
Alongside this, you can use methylene blue. Treatment should be applied for a week straight with regular water changes.
Add Fast-Growing Plants
Aquarium plants can work to limit the amount of bacteria and algae that grows wild in your tank. That’s especially true for fast-growing types that can head-off an ongoing problem.
Added a few stable types of plants to increase oxygen levels, maintain consistent quality in the water, and give your angelfish somewhere to hide. The best plants that grow quickly include:
- Amazon sword
- Water wisteria
- Green foxtail
- Java moss
How Long Does Fin Rot Take To Heal?
How long it takes your angelfish to heal depends on the severity of its fin rot. It should take a few weeks to recover if you follow the instructions for your antibiotic to the letter.
Once the disease is gone, healing takes about 4 to 5 days with gentle fin rot. Serious fin rot takes 5 to 7 weeks to recover.
Can Fin Rot Kill Angelfish?
If left untreated, fin rot will kill your angelfish. If you notice the symptoms, you should respond immediately. Once the infection has gotten out of hand and escalated into the late-stages, your angel’s life expectancy will be reduced to just a few weeks.
Is Fin Rot Contagious?
Fin rot is highly infectious and can spread throughout an entire tank. Since it’s caused by gram-negative bacteria, the illness creates a slimy coating on your fish. This outer membrane can easily leech into the water and stick to other fish.
Since angelfish are known to viciously defend their territory, your sickly angelfish might also rub the bacteria off on its tank mates during a conflict.
If the bacteria grow out of control, the contaminated water will even make your filter into a carrier of the disease. The sponges or collection cups will harbor the fin rot disease and spread it back into the water, even once you’ve cleaned the tank. As such, if you notice fin rot in your tank, you should clean the entire area thoroughly.
Can Angelfish Regrow Fins?
If your fish is healthy and recovering, it may regrow parts of its fins. The tail and side fins closely resemble flesh, with layers of skin covering bony spines. These can regenerate over 4-6 weeks, with smaller chunks growing in faster than big chunks.
However, if the fish has completely lost its fins, it cannot regrow them. The blood vessels, nerves, and tissue will be so damaged that it can’t recover.
How To Prevent Fin Rot
Although fin rot is a common disease, it can be prevented and handled easily. According to Fisheries Science And Aquaculture, environmental issues and stress are the leading cause. So long as you keep your tank healthy, well balanced, and help the fish avoid conflict, they are less likely to get fin rot.
- Clean your tank once a week, changing 20-30% of the water
- Check and balance the pH level of your aquarium
- If you want to buy more fish, also invest in a larger tank. Angelfish will be most comfortable in 55 gallons or more.
- Avoid overfeeding your angelfish, as they may get constipated and ill
- Remove any food that isn’t eaten within 2 minutes
- Separate fish that bite at each other’s fins and tails, as this can create an open wound that bacteria will infect
All in all, your fish will be able to safely weather a case of fin rot. Just be sure to quarantine the diseased fish, use antibiotics, and keep an eye on the other fish in the tank. If the problem escalates, you can speak to a vet about stronger medications.