These guys are the "monsters" mentioned in my other African cichlid thread. These are also cichlids, but they are native to either South or Central America, depending on the fish. They are what are referred to as wet pets in the hobby, very large, very intelligent fish with very individual personalities.
This is Talon, a Midas cichlid. He's 10 years old, and 14" long. His species is aggressive and so he lives by himself.
This is Craven, another Midas. He's about 6 or 7 years old, smaller than Talon at about 11" in size, but he's much more aggressive than Talon. I can't put my hand in the tank without him attacking it, and he has the power to break a finger if he gets in a good bite. He also lives solo.
This guy is Griffen. He's a Flowerhorn, which is actually a man-made hybrid. There are all kinds of different variants of Flowerhorns - Griffen is what's called a Thai Silk. High quality specimens of the various kinds sell for hundreds or thousands of dollars, but there are a ton of "everyday" ones out there as well. He's currently a juvenile, only about 7" in size, but should mature to about 12-14" and will likely become very aggressive like Craven. He's a solo bachelor also.
This is Griffen, he's a Texas cichlid. He's the "mini monster" compared to the rest - only about 9" in size and full grown at 2 years old. He's also alone, but he's no where near as aggressive as the others I've listed so far.