I have a betta fish with shredded fins out of nowhere. I got him a little over a month ago and have in a 10gal tank with

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Customer: I have a betta fish with shredded fins out of nowhere. I got him a little over a month ago and have in a 10gal tank with temp 78-80F. First week he windowed surfed entire time and hardly ate. I added a 3 foot plant and it helped instantly. But 3 days later his fins looks shredded. I cleaned tank and he started window surfing ever since. He still eats fine and is active. His fins seem to grow back some then get worse again. I don’t know what to do now. I’ve tried treatments and water quality comes back good. I thought maybe it’s the decor but he went entire week with the decor and no problems. Any ideas?
JA: A lack of appetite can seem worrying. The Expert will know how to help. Does the betta fish seem to be in any pain?
Customer: No, color looks good and he’s very active and eats fine now. Only problem is fins.
JA: What's the betta fish's name?
Customer: His name is*****’s red with a long tail. Don’t know exact name of his kind
JA: Is there anything else the Vet should know about Murph?
Customer: i think that about covers it.
Answered by Terri in 8 hours 2 years ago
20+ years of experience

48,376 satisfied customers

Specialities include: Dog Veterinary, Cat Veterinary, Bird Veterinary, Reptile Veterinary, Exotic Animal Veterinary

Fin rot is caused by bacteria

  1. Take the affected fish out of the tank. Start by removing the affected fish from the tank and placing him in a separate tank with clean, fresh unchlorinated water.[2][3]
    • You will also need to remove the other fish in the tank to a separate container with clean, fresh unchlorinated water. Use a different net to remove the other fish as fish rot can be spread through shared nets. Do not place the affected fish in the same container as the other fish as this can cause the fin rot to spread.

Wash the tank and all the tank accessories. You will then need to drain the tank of all the water in the sink. Take out all the tank accessories as well as the gravel in the tank.[4][5]

  • Give the tank a good wash with hot water. Do not use soap when you clean the tank. Use paper towels to get into the crevices of the tank and make sure it has been cleaned thoroughly.
  • Soak the tank accessories in hot water for five to ten minutes. If you have live plants, soak them in lukewarm water. You can then take them out of the water and let them air dry.
  • Wash the gravel with warm water and hoover it with a small vacuum to get rid of any dirt or debris.

Do a 100% water change. Once you have washed the tank thoroughly and let it air dry, you can place the gravel and the tank accessories back into the tank. If your tank is uncycled, do a 100% water change using dechlorinated or conditioned water. Make sure the water is at 80-82 degrees F (26-27 degrees C).[6]

  • If your tank is cycled, meaning there is an established colony of beneficial bacteria built up on the submerged surfaces of the tank (accumulated mainly through fish living in the tank and excreting nitrogen), you can do a 50% water change; subsequent smaller proportion water changes are recommended.[7]
  • If your tank has a water filter, you should take a bucket of the fresh tank water and wash the filter with the water. Once the filter is cleaned of any gunk or dirt, you can place it in the tank. Do not use tap water to clean the filter as this can contaminate the filter.

Check the pH of the tank water. Before you put your fish back in the tank, you should use a pH test kit to ensure the water quality is good. The pH should be around 7-8 and the ammonia, zero nitrites and nitrates should be no higher than 40 ppm.[8]

  • Once you have confirmed the water is suitable for your fish, you can slowly add the fish back into the tank, including the fish with fin rot. You may then add antibiotics or antifungal medication to the tank water to help kill the fin rot. The combination of a clean tank and medication should help your fish to get rid of the fin rot.

I hope this information has been helpful. I will be standing by if you have other questions. Let me know if I can help further. Also, before signing off today, please take the time to use the star rating system at the top of the page to leave a rating for me (bottom of the page if using the app). A 5-star rating is appreciated as top notch answers are my focus. If you feel you have received anything less, please reply so that I may help until you’ve received the assistance you need. Until you issue a rating, the website will not compensate me for helping you. You will still be able to chat with me even after issuing a rating at no further charge on this thread.

Kind regards,


Here's a picture of his tail and tank just to make sure you don't think it could be something else. Ph is about 6.5 and everything comes back good too.

Murph has some fin rot due to bacteria being introduced into his tank,

Follow the above directions to clean and disinfect the tank and he should recover completely

Isn't there supposed to be bacteria in his tank? Is it because I may have put too much in or what?

some bacteria is good but bad bacteria is harming Murph.


Add Bettafix to the tank as will as a through cleaning


Last question. I guess I'll buy and one of those temporary tanks while I do this, but how long should I wait to put him back in? Can I put him back in same day I clean everything or am I going to need wait a few days? I don't want to stress him anymore than I already have by keeping him in a smaller tank.

yes, you can put him back in his tank the same day after you have cleaned it done the water change and added bettafix

Ok thank you

my pleasure

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