Curled gills are usually a sign of stress. The ammonia levels are a bit high.., 2.5 isn’t terrible, but 0-1 is usually ideal. To reduce the amount of ammonia in your tank, make sure to clean up any food that your axie hasn’t eaten and do water changes regularly. If you have a strong filtration system, sometimes it can move your axie’s gills a bit. To see if it might be due to the filtration, let your axolotl swim around and see if the position of their gills changes.