Need help, angelfish has red growth on fin, and looks to be getting weak!



20 gallon tank
Tank has been running for 2 years.
I have a HOB filter installed.
I have a heater in the tank.
Water temperature is 79.
There is 1 angelfish, 4 neon tetras, 2 penguin tetras, 2 emperor tetras, 2 algae eaters, and 1 upside down catfish.

I change the water every 2 weeks.
I change 20% every time.
I do not treat the water, and put in tap water.
I only change out the water.

*Parameters - Very Important
Yes, waited a few weeks before adding fish into the tank.
I use Api master test kit to test the waters.
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Nitrite: 0
Nitrate: 5.0
pH: 7.0

I feed them once per day.
I feed about half a teaspoon of flakes every time.
I feed them tetra flakes

Illness & Symptoms
I have had this fish for 2 years.
I noticed them about 1 month ago.
The angelfish has not done anything strange so far, but it does seem like this growth is getting worse.
I am unsure of what illness the fish has, and i have only been doing more frequent water changes.
Fish was not ill or injured when i purchased it.
Only the fin has this red growth, and the behavior remains the same.

At first, the growth started as white, and i mostly ignored it as i thought it would go away. Slowly, it started to turn red, and i started changing the water more, but it hasnt gotten any better. Its behavior hasn't changed, but i'm still worried about it.

Any help would be greatly appreciated, thanks in advance!



Hello, not sure what that is on his fin but his other fins are looking quite frayed. Your ammonia reading should be 0, if you have trace amounts it is very toxic for your fish, maybe this is the problem and your beneficial bacteria population is too low causing a mini-cycle? \When you do a water change, do you ensure that the tap water has been sitting out for at least 24 hours to get rid of the chlorine and that the temperature of the water is 79 like the tank when you add the new water? I would buy some water conditioner to treat your tap water. You only need to use a little bit, one bottle goes a long way.... your beneficial bacteria and fish will thank you for it.


I think it might be a bacteria infection. My angel had one and was quite ill for several weeks but eventually she heal on her own without treatment but it wasn't quite as bad. She maybe bizaliz3 or angelcraze have run across it before.

If the ammonia is .25 or lower i doubt it is a direct cause of ammonia poisoning unless it was previously higher. Still to be safe you can put a few drops of sachem prime in the water.
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