Well,when I first had my 55 gallon set up,I had the Oscar,Jack Dempsey,Severum,Green Terror in the set up,but less than a year later,I upgraded to a 125 gallon tank,where I am able to have more options for stocking fishes.So I don't see why you can't have a JD included,they all grow slow,except you may expect your JD to outgrow them quicker.