Interest in Jack Dempesy Cichlids

My girlfriends father has african cichlids and I think they are so interesting. Myself I have barbs but am looking to invest in a larger tank (20 gallon). Im not sure what to put into it, my girlfriend and I have been discussing and we were either going to go for community or species.

Im very interested in the Jack Dempsey cichlid. I am aware of their aggressive territorial nature, but I find them to be so interesting. When I got my barbs, I was intrigued with the Jack Dempseys. Also, from my brief time in the pet store they seemed to be among the most interesting fish.

Now here are my questions:

1. will 20 gallons be big enough for 2-3 fish
2. will the fish kill each other??
3. what are my chances of possibly breeding these fish down the road
4. any good, informative books about jack dempseys?
 
A 20 gallon tank is way to small for one Jack Dempsey. They grow to about 9" and for they first months, they are suppose to grow about 1" a month. I guess you could keep one or two small Jack Dempsey's in there (while they are small) but I wouldn't reccomend it. I am setting up a 75 gallon tank and I am only planning on having about 3 or 4 JD's in there.
 
I know they are beautiful but they are not an outgoing fish. if u want to see the fish & recieve interaction, JD isn't it, at least not the ones I've kept.
 
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