What’s happening with my fish

The first photo is when I first got him the second photo was from today. He has a hide on the way but until then he’s been hiding in this blue plant. I just wanna know what’s with the sudden burst of blue and the shortening of the fins. He’s in a five gallon tank filtered and heated he has had two tank mates since I got him two glow fish. I don’t know if the little guys adapting with colors and physical appearance or if he’s actually sick. But if he was sick why would he be such a bright blue? 🤔

All help and advise is appreciated