well as a fishman and lmb keeper for awhile, usually it all depends where they come from. water clarity is the biggest factor. i had fish from our local muddy river, and he stated as silverish color you speak of, until he was chasing feeders. they change with moods also. the darker the water the lighter the fish. but over time, they adapt to tank settings and green up very nice. and you will actually notice the change of the lat. line darking during feeding. but also you have to remember the lmb is the top predator in most food chains and depend mostly on surprise attacks, so they adapt to "all" surrounding over time. damn i love lmb