Your white finned ones are probably blue acaras, they are cousins of the green terror, but are rare you could say, but they are a different fish, but they do lok similar. They are often sold as green terrors at the LFS, bkuz the LFS doesnt know the differnece or because they were sent them all in the same order as green terrors, but the blue acaras are less tempermental than the GT, and not as aggresssive. Passive in my view as i house many in my tanks.