I started with four of these. Within a couple of weeks this one decided it was the dominant one. It seemed as if it didn’t even want the others to eat.
It is interesting how much different it looks depending on the lighting and background.
I hear you about the color change. I moved Thor to my other tank for a bit and his normal black background color turned tan. Now back in his tank it's black again. If you can use black substrate, it makes Thor darken up.
Don't expect quick growth from them. My Saggitae Casper has already gained two inches on Thor.