"Inferring from the molecular evidence I obtained (both mitochondrial and nuclear), the Electric Blue is a Jack Dempsey. I don't know where the rumor started about it being a hybrid with tetracanthus but I can assure you that it is not. The (Electric) Blue Dempsey does not appear to occur in the wild, I would speculate that the color morph appears because of inbreeding within the aquarium trade. Hope that helps, Prosanta"
 
So, according to Dr. Chakrabarty, the Electric Blue Jack Dempsey is a color variety of the Jack Dempsey, and not a hybrid with another species.

Sometimes these fish appear in books and other websites under more than one name, and that is why we show more than one name in the table. A living organism can really only have one scientific name at one time, but the correct names can change as scientists learn more about the fish and the history of its scientific name.

In the table above the upper scientific name is the newer name, and the lower scientific name is the older name. You can see that the genus Cichlasoma is apparently being split into Archocentrus, Heros, Thoricthys, Nandopsis, and more names that are not listed in this table.

The maximum sizes are not really the maximum. I have occasionally seen specimens of each of these fish that are bigger than the sizes listed as the maximum in the above table. But fish of the sizes listed would be considered very big for that species.

Fish like these Neotropical Cichlids continue to grow their entire lives. Mammals like dogs and cats grow to their maximum size within a few years, stay at that size for several years, then often decrease in size the last few years of their lives. But Neotropical Cichlids continue to grow for their entire lives. So the term maximum size is a bit more vague when applied to these fish.

The sizes listed above should be an important guide when buying fish. Be sure you are committed to providing the fish you buy with an appropriate home. Each of these fish will eventually need a big aquarium.

Click here to go to another web site which has lots of very interesting details about Cichlids.

Comments
Neotropical Cichlids are generally very aggressive. Most other tropical fish cannot live with these fish. As they mature these fish change colors. Often the males become more colorful, but sometimes the females become more colorful than the males.

After they mature, the males begin to create a territory and chase other fish out of their territory. They want to attract a female to their territory, then go through a ritualized test battle with her. Presumably each fish testing the strength of the other.

Once a pair bond is established, the two fish work together to defend their territory, spawn, and raise their baby fish. Click here for more about breeding the Pink Convict shown below.

Recommended Diet
When Neotropical Cichlids are small, feed them floating flake food. Also feed them some freeze dried blood worms and give them an occasional treat of live or frozen brine shrimp. When Neotropical Cichlids have grown to be about 2.5 inches, they will usually need to start eating pellet food such as Hikari Cichlid Pellets. This food is available in most stores that sell pet fish.
 
Also feed them an occasional treat of live Black Worms and some live or frozen brine shrimp. Click here for more about feeding fish. Some of these Neotropical Cichlids, for example Convicts, seem to do better when fed a few Black Worms. But other Neotropical Cichlids, such as Firemouths, often seem to get bloat when fed worms. Click here for more about Black Worms.

Compatibility 
Either one of these fish to an aquarium or more than 3. If you keep just 2 or 3 of these fish in the same aquarium, the strongest one will make the others miserable, but they will usually do very well in a group of 6 or more in a large aquarium with 50 gallons or more of water.

Jack Dempseys and Red Devils may be too aggressive for some of the other fish in this group such as the Green Severums. These Neotropical Cichlids are often kept with a Plecostomus or a Bushy Nose Pleco, White Tip Shark Cats and Pacus.
 
Click here to read more about several other groups of compatible fish.