Curled gills

[gfsward]

Hey all,
This might just be over-worrying but figured better safe than sorry. I know that when an axies gills are forward that's a sign of stress. My axies gills are curling forward right now and I don't know why. I've done a couple water changes and double checked the temperature.
If someone could let me know what's going on that would be great.
Thank you!

 

[xcoregamerskill]

Make sure the flow from your filter isn't too strong.

 

[gfsward]

There isn't any flow, I have a sponge filter