mine has killed 2 adult jags so far...they are very aggressive, especially once they surpass 15" it is very hard to add a tankmate without damage or death unless they were raised with the dorado since very young age.
jags were around 10-11"...dont really want to mix anything else with him and I dont keep any cichlids other than peacockbass, I had only put the jags in there because they were too small to put in with any of my other fish and didnt want to just throw them out.