Strange behavior

[newbie hob]

I have a wag tail platy, sharing some fry in a 30 ltr tank, for the past couple of days my orange platy is smudging its self into the side of the aquarium which is about 20 cm width and zooming (realy fast) across it all day she hardly swims across the tank anymore, all water readings are normal, and I am changing 15% water (dechlorinated water) every day, I didn’t do any thing different than the regular water change.

 

[WILDER]

Can you see any little white spots on her, does it look like she has been sprinkled with salt, sometimes they do rub against things when you have changed the water, check water for ammonia,nitrite,nitrate,and ph, as if you have alot of fry in the tank it can quickly change your test results.