75 Gallon Tank Glass surfing, sick or disturbed?

[Sb092]

I have a 75 gallon that has been set up for at least 5 years. Current stock is 5 pearl gourami’s and three blue gourami (not the dwarfs, the bugger stripped ones, and the bane is escaping me at the moment). I recently added 2 kuhli loaches about a week ago. I wanted to see how they did before adding more. Two days ago I did purchase 4 more. I have a total of six. Today was water change day…. Ever since I changed the water, a few of them have been glass surfing and doing barrel rolls along the glass. I will attempt to attach the video….. I never owned these fish before. Is this normal behavior or should I be concerned?

 

[A201]

The slight parameter and temperature differences that occur during a water change can cause fish to flash & dart around a little abnormally.

I'm not sure if that's what is going on in this situation.

The Kuhlis are acting more like YoYo Loaches. Lol

Try turning off the lights. That often tones down glass surfing.