they are black arowana... at least thats how they where first classified. they do have a blue/turquoise tint to their fins, grow slightly slower and smaller than silvers but are closely linked to silvers. both from the amazon. Blacks are still all wild caught so, it's very rare for blacks to get drop eye too, whch is a bonus! Carefull though lfs calling blacks blue's tend to sell for twice the price... so check the price first if you are considering...