It's true that such lists are extremely generalized and don't factor in myriad variables that can affect behavior nor those individuals who are statistical outliers. The wackiest cichlid I've had was--totally not kidding--a demented electric blue Acara. There was just something wrong with him.
However I don't think the lists are completely useless. Hearing others' experiences and having even a general idea of the types of cichlids that tend to exhibit more or less aggressive behavior overall is helpful, especially to a total beginner pondering their very first cichlid tank and wondering, "Can I put a pretty Red Terror in with my pretty angelfish?"
In my experience, the most aggressive / territorial / predatory cichlids I've kept so far (excepting the deviant EBA) are:
1 - Red Devil, A. labiatus. Holy cow. I wouldn't even consider putting another fish in his tank. Nero's a great wet pet and loves toys like his rubber ball, but if I invade his tank he responds with righteous indignation and goes right for my hands. His bite packs a wallop. He also delights in scaring the cats away from my rack of breeding tanks.
2 - Red Texas. Serious anger management issues. Caligula can coexist with other very aggressive cichlids but he is the undisputed ruler and kills anyone who looks at him funny without a moment's hesitation. Not shy about chomping me either and he also has a nasty bite. He paired off with my dominant female festae and I moved them to their own tank before they could go into full-blown murder mode. He's actually quite gentlemanly to her most of the time.
3 - Jewel cichlid, H. bimaculatus. Small. Cute. Shared a tank with the Red Texas and festae and frequently engaged in hit-and-run attacks, nipping chunks out of the fins of the bigger fish and then darting for cover... only to do it all over again just for kicks. They can't inflict a whole lot of damage on much bigger fish but they are tough and scrappy. They punch above their weight class. They'd most assuredly kill many other fish closer in size or not aggressive enough to stand up to them. Their speed allows them to get away with those sneak attacks most of the time but finally a festae got lucky, grabbed one and chewed him nearly in half. Not so tough once they're caught.
4 - Red Terror, M. festae. Hardcore and quick to dismantle other fish with very little provocation. When not spawning, they can live with carefully chosen tank mates though. My Red Texas and his festae girlfriend actually get along very well and rarely squabble.
5 - Texas cichlid, H. carpintis. I had a female that killed everything she could in my aggressive tank. Frustrated, I moved her to my very aggressive tank. She tried to seduce the Red Texas. He was not interested and immediately killed her, abruptly ending her reign of fear.
6 - Convicts, A. nigrofasciatus. Little scrappers. They just love a good fight. Utterly fearless when spawning.
7 - Jack Dempsey, R. octofasciata. Not a wimp and prone to picking on anyone he thinks he can take. Putting firemouths in with him was a dumb idea. Firemouths are mostly bluff and very little bite. The JD is quick to call that bluff. I separated them. The convicts give him hell though.
However I don't think the lists are completely useless. Hearing others' experiences and having even a general idea of the types of cichlids that tend to exhibit more or less aggressive behavior overall is helpful, especially to a total beginner pondering their very first cichlid tank and wondering, "Can I put a pretty Red Terror in with my pretty angelfish?"
In my experience, the most aggressive / territorial / predatory cichlids I've kept so far (excepting the deviant EBA) are:
1 - Red Devil, A. labiatus. Holy cow. I wouldn't even consider putting another fish in his tank. Nero's a great wet pet and loves toys like his rubber ball, but if I invade his tank he responds with righteous indignation and goes right for my hands. His bite packs a wallop. He also delights in scaring the cats away from my rack of breeding tanks.
2 - Red Texas. Serious anger management issues. Caligula can coexist with other very aggressive cichlids but he is the undisputed ruler and kills anyone who looks at him funny without a moment's hesitation. Not shy about chomping me either and he also has a nasty bite. He paired off with my dominant female festae and I moved them to their own tank before they could go into full-blown murder mode. He's actually quite gentlemanly to her most of the time.
3 - Jewel cichlid, H. bimaculatus. Small. Cute. Shared a tank with the Red Texas and festae and frequently engaged in hit-and-run attacks, nipping chunks out of the fins of the bigger fish and then darting for cover... only to do it all over again just for kicks. They can't inflict a whole lot of damage on much bigger fish but they are tough and scrappy. They punch above their weight class. They'd most assuredly kill many other fish closer in size or not aggressive enough to stand up to them. Their speed allows them to get away with those sneak attacks most of the time but finally a festae got lucky, grabbed one and chewed him nearly in half. Not so tough once they're caught.
4 - Red Terror, M. festae. Hardcore and quick to dismantle other fish with very little provocation. When not spawning, they can live with carefully chosen tank mates though. My Red Texas and his festae girlfriend actually get along very well and rarely squabble.
5 - Texas cichlid, H. carpintis. I had a female that killed everything she could in my aggressive tank. Frustrated, I moved her to my very aggressive tank. She tried to seduce the Red Texas. He was not interested and immediately killed her, abruptly ending her reign of fear.
6 - Convicts, A. nigrofasciatus. Little scrappers. They just love a good fight. Utterly fearless when spawning.
7 - Jack Dempsey, R. octofasciata. Not a wimp and prone to picking on anyone he thinks he can take. Putting firemouths in with him was a dumb idea. Firemouths are mostly bluff and very little bite. The JD is quick to call that bluff. I separated them. The convicts give him hell though.
