Even if they want to mate, they can't mate.
Scats spawn in full marine environments. They spawn in the ocean. The actual breeding habits of scats are a mystery in themself, never heard of them successfully breeding in captivity, and had no luck whatsoever in my years of attempts.
Your scats still look very colorful. I'll post a few pics of mine tonight, they start to become very dark and less attractive as they grow older. Unfortunate since they're a great species.
You can maximize their health and coloration by acclimating them to a full marine environment as they mature. About six months ago I acclimated my eel and scats to marine salt levels, and the green scat hasnt stopped growing darker, but he has developed even more of an appetite, which is always a good sign.