I'm just a worrier but today I noticed something on Crusoe I do not like and noticed he has had a change in behavior. Normally he is always swimming around and immediately comes out of his hiding spot when I approach the tank. His motions are usually fluid and he will chase anything that gets near the tank.
Since I put in his new filter and heater, however, he has changed his behavior in that he no longer comes out of his hiding spot when I approach the tank, his movements seem a bit jerky, he won't pay attention to moving objects outside his tank, and I spot this shiny coloration under his gills that I did not see before and do not like as a result.
Here are some pictures of the shiny bit. In some photos, I use an LED flashlight to highlight them. Note that his body scales normally glow when light shines on them, usually a whitish-purple.
Is this just something I have not noticed before? His water conditions are normal. I am doing a fish-in cycle and just vacuumed his water. He seems to be moving around more since I did, so I wonder if it was just something in the water that caused him to change his behavior.