I have an otherwise healthy puffer that's about 5 inches long that just started showing these spots on his back today. He was perfectly fine yesterday and was eating with his normal huge appetite. Water parameters are normal and all his tank mates are not showing any signs of disease. He's been laying on the bottom in a cave breathing heavily today which is unusual for him. My research has me thinking maybe a sub dermal bacterial infection from an injury?
Any help diagnosing this would be greatly appreciated. Thank you in advance!