mine is rather skittish , at times flying across the tank when i come over to begin feeding. Runs from the larger oscar and even my severum. However when truly threatened hes been quite nasty and has put both the other fish in there place, ripping off half of one of the oscars trialing fins by his belly, and tearing a chunk from the severums tail as well when the severum repeatedly harrassed him.
I truly fear he may jump out of the tank or injure himself severely by crashing into the decor. I bought him almost fully grown at my LFS. definitely one of the more spectacular JD's ive ever seen, but 50% of his tail was missing so I got a good price. He was grown out in a tank with very aggressive tank mates(as the tail showed)