First I'll direct you to where you can find many answers.
http://bluejax.co.uk/default.aspx
?'s
How big and old is your blue?
Where did you get him from? (do you know his breeder)
Water changes once week minimum with blues. 20-30%
How's he eating and what? ( frozen bloodworms, brine shrimp a must)
Food soaked in garlic guard does wonders.
Filtration? Air stone will help too.
Your tank mates are okay. Down the road you may want another smaller jd to keep him company. I would not recommend putting other aggressive fish in with him until he reaches maturity.
I've kept blues for over a year now. I currently have 2 adults and 3 juveniles. Great fish that need a little extra care and time. Diet is also very important. Check out the link and join. Ask a question and get ready. You'll get a lot of advice. Good luck, Rich