Is this normal

Hi guys, so I recently bought 6 kuhli loaches and put them in this tank. It’s got lots of hiding spots, sand, fluval substrate and plants. The tank has also been fully cycled. This is the second day I’ve had them in there. They were normal last night with very little zoomies but today as soon as I turned the fishtank light on they’ve gone crazy.

I saw on another post someone saying if there’s storms coming they do this as well or it can be window surfing. But I don’t know what could be wrong with the tank. I know the drift wood has biofilm but that’s cause it’s only recently been put in and I’ve scrubbed it off and done a water change at least once since putting the drift wood in.