Dwarf cichlids are all quite aggressive except for the Rams and grow quite large....they should also be kept as a couple if it is a Ram or in a Harem for the agassizi. I really would not recommend only keeping 1 of these as alone they are quite miserable. Also not sure if your Endlers would survive in the long run as they are quite small...the babies definately will not have a chance.
Just my opinion... you can read up a lot about the proper keeping of dwarf cichlides on Apistogramma.com
How about a harem Dario Dario? Check my blog below there is a foto of one at the top of the page at the moment
Good luck in your search
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