Abnormal swimming behavior

[PicaGaG]

Please help me.
English isn't my first language, I used a translator for these messages, so they might not be entirely accurate.


Since yesterday, my flagfin has been swimming rapidly back and forth along the sides of the tank. My initial thought was that it could be parasites or overstress.

I gave it a freshwater dip and ruled out Neobenedenia. What could be the cause?
I hope the video uploaded correctly.

 

[PicaGaG]

 

[vetteguy53081]

I see a healthy and active fish here and tank is very clean and suggests it is seeing its reflection and trailing back and forth not abnormal. As FW dips are stressful to fish, refrain from doing this unless absolutely necessary

 

[PicaGaG]

As FW dips are stressful to fish, refrain from doing this unless absolutely necessary

"Thanks, but he's never done this before. He suddenly started swimming back and forth really fast, when he used to be so calm. I'm a bit concerned the new fish may have brought in parasites."

 

[PicaGaG]

This is how he used to swim.

 

[Jay Hemdal Verified Community Expert]

"Thanks, but he's never done this before. He suddenly started swimming back and forth really fast, when he used to be so calm. I'm a bit concerned the new fish may have brought in parasites."

I call that “pacing” similar to a tiger in a cage. It seems to be stress related, but can also be a learned behavior.

Is the fish still feeding normally?

 

[PicaGaG]

I call that “pacing” similar to a tiger in a cage. It seems to be stress related, but can also be a learned behavior.

Is the fish still feeding normally?

He chases food just like before and shows no abnormalities in this regard.

He's the largest in the tank — the others are at least 1.5 inches smaller than him.