Name: Amphilophus labiatus
Origin: Central America
Red Devil is a must own fish. I had 2 Red Devils that were about 18 cm long in a 220 liter tank and they had a beautiful rich red color. They are very territorial and hostile toward others of the same kind and other types of fish. They will eat anything eatable that fits in their mouths. I fed them goldfish and store box shrimp and Hikari Cichlid Gold pellets. As they grow to adulthood the male starts to get a bump on top of the head. Red Devil will eventually become the king of the aquarium if kept with other fishes. When they are fry they are pretty ugly (at least to me) as they have no red and are grayish and blackish, but as they grow up they start to get the red and they tend to grow up pretty fast. To obtain the rich red color they must be fed properly. I have had my Red Devils with Oscars and Green Terrors and a Texas Cichlid, but none of these fishes can compare or come close to the Red Devil's vicious life style from my experience.
I have been keeping these fish for years and, if kept in 1000 liter tanks, they are generally calm. if kept in smaller tanks they are very aggressive and no fish will be able to survive the beating these fish can dish out. They will eat live meals and also fish pellets. They can get up to 40 cm long!
Its common name “red devil” pretty much describes the behavior of this fish. Unless kept in a very large aquarium such as a 1500 liters, the chances of it living peaceably with other fish is very slim. It will kill other fish relentlessly and without hesitation in a small tank, even bottom feeders which most other aggressive fish do not mind. So, if you want one of these fish, be prepared to keep one in a tank of its own. A minimum tank size that I would recommend for one is a 200 liter tank. Besides the down side to them, they are very beautiful and I consider them to have lots of personality because they can interact with their owners. It's quite funny how they try to attack you through the glass.
I have a 9 year old red devil, which I bought for 5 dollars when he was about 3 cm long. He is about 30 cm long and should weigh about 1.2 kg now. I purchased two others at the same time, which he promtly killed. I keep him in a tank on his own, as there isn't much room for anything else. He has a huge lump on his head and pushes all the gravel up to one end of the tank so we call him Dozer. He is definitely a one person fish and refuses to eat anything offered to him by anyone other than myself. He especially hates my wife and aggressively attacks the glass any time she passes the tank. When we have gone on holidays for up to six weeks he will still refrain from eating anything from the housesitter, and is a bit funny for a week or two towards me. He has been reared on fish pellets intended for farmed fish, and flatly refuses to eat anything else including live foods. The bit I like about him though is the reaction he gets from new visitors to our home which is usually "Holy Hell! Check out the fish!"
I have had over 20 years experience dealing with Red Devils (and almost every other cichlid imaginable) and would agree with many of your inputs--they will eliminate any other fish after they reach about 20 cm long and they do tend to follow their owner around. I have found only fish that is compatible with them--schools of African Cichlids. I have a 570 L tank and about 10 other africans that the Red Devil chases, but can't catch. In fact, the cichlids toy with her and bite her tail but scurry into a cave when she's provoked. She is now about 25 cm long and pretty aggressive. Before her I housed a male Red Devil 14 years old in the same 570 L that killed Dempseys, Oscars, Jaguars, Convicts, Flower Horns, and too many to even remember. He was ultra aggressive, but I discovered the secret when mixing him with African Cichlids: he couldn't catch them and they have plenty of space to hide. This combo will work in a larger tank.
I must have the only calm, vegetarian red devil alive. He is about 7 years old, 35 cm long and thinks he is a dog. He loves to be petted (yes, petted) follows me around the room at every move I make, splashes the water when hungry or upset and hides in the corner when scared. He will NOT eat anything live, I once gave him goldfish feeders and he swam with them as if he thought they were his little buddies. He only eats Hikari Cichlid Gold food, spits ANYTHING else right out. He currently lives with a smaller African Cichlid that is 1/10th his size yet picks on him constantly. So, not all Red Devils are truly devils, mine has decided to be a 'dog in the water'.