fin rot wont go away

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New Member
Jan 27, 2021
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this is my first betta ive gotten. a couple weeks after i got him, i was unable to go to the house with the fish because it was contaminated with covid. when i got back, my fish had fin rot. this was around the beginning of the year. i immediately did a full tank clean, took out sharp decor, and used test strips (i was waiting on my order for the api liquid test kit) my fish also had swim bladder disease so i gave him epsom salt baths. when he was back to normal, the fin rot got worst. i used melafix, pimafix, aquarium salt, i put in live plants, i do daily water changes (30%), i got a sponge filter (the other filter’s flow was too strong) i have api fin and body cure but i have yet to use it. ive spent so much money on medication. im out of ideas. ive read every article, watched every video on fin rot. it just wont get better. when i tested the water the ammonia and nitrite were 0 ppm and the nitrate was 5. the ph was 7.8. the water temp is 79/80° and hes in a 10 gallon tank. this might be useless information but i use prime conditioner, and feed him aqueon pellets, and occasionally frozen bloodworms and frozen dried blood worms. there are three moss balls in the tank and one java fern plant. here are some pictures (1st one is january 18, 2nd one is january 27)


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Fish Guru
Jan 26, 2008
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Perth, WA
Normally you can treat fin rot with big daily water changes, cleaning the substrate and filter, and adding rock salt (sodium chloride). If it doesn't clear up after a couple of weeks of that, you add a broad spectrum fish medication that contains formaldehyde or acriflavine. If that fails then anti-biotics, but they should be used as a last resort when all else has failed.

Wipe the inside of the glass down with a clean fish sponge.

Do a 75% water change and gravel clean the substrate every day for 2 weeks. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use them. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens.

Increase surface turbulence/ aeration when using salt or medications because they reduce the dissolved oxygen in the water.

Add some salt.

You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

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