Ever heard of fish missing the sun?
I think it happened to me this morning. With the blinds open the sun will shine about 3 hours in the morning into about 1/3 of the tank. After I fed the fish, my Jawfish retreated back to his den for a few minutes, then wandered out to where the sun was shining. I've never seen him make it this far because it was on the complete opposite side of the tank.
So he's on the side of the tank and is going crazy looking into the sun; his mouth opening and making quick, jerking movements at the glass. At first I thought he just forgot how to get back to his den, but it looked as if he wanted to get closer to the sun. I was able to get really close to him and take several pictures and he didn't move; which really made me curious because near his den, he'll barely poke his head out when I'm around.
Stressed? When I thought about that, I immediately checked the water:
Finally, after about 20minutes of dancing in the sun, he slowly swam back to his cave and everything is back to normal. Since he wasn't tank bred, and I bought him online about 2 hours after they posted new livestock, it looks like he just missed the sun!