Originally Posted by lilnaugrim
Yeah usually around 6 months is a good way to calculate. I know my boy in my avatar was only about 4 months when I got him because he wasn't very big and his fins still had lots of growing to do.
As far as adding brown or dark colors, that would be them brightening I believe you mean? if not and literally changing to brown or dark colors then that's more like marbling and not due to age or anything.
Well to put it into perspective, Buckshot used to have a nice thick blue streak on his back. It has now, from when I got him to now, has almost become nonexistent. He's gotten much darker (like a blackish navy blue) and sometimes instead of the dark blackish blue he'll be a tint of red. He's a weirdly colored guy.