Any reason why fin rot can suddenly rebound?

[Lexi B]

I've got a Betta that had been recovering from a bad case of fin rot back in December. His rot came from a combination of stress and poor water quality after his aquarium had been shattered. He was healing up like normal, but about a week ago the fin rot was suddenly back. After checking his parameters, temperatures, and good expiration dates I didn't find anything to be amiss. 

 

He's on his second round of maracyn now, I'm just really puzzled as to why it suddenly developed. Is it because his fins were still recovering? 

[Fishguy]

Did he get injured during the healing process? Did you check the water parameters while he was recovering if not do so and please tell what they are. Was there any kind of sudden change during the healing process, anything.

I don't think it is because he was still healing. 

 

[Lexi B]

On 3/30/2022 at 2:22 PM, Fishguy said:

Did he get injured during the healing process? Did you check the water parameters while he was recovering if not do so and please tell what they are. Was there any kind of sudden change during the healing process, anything.

I don't think it is because he was still healing. 

 

Nothing sudden. The parameters have been consistent. 

0 ammonia 

0 nitrite

20 ish nitrates -planted tank

7.6 ph

5 kh

3 gh

Temp is 78