Thinking about starting a silver arowana community tank. I have a 13" -15" silver arowana now. I want to add 2 or 3 more to make a community tank but not sure on what number works best and if it's to late since my current aro is so big. Looking for any input or advice. Got a 240 gallon 2 x 8. Going to upgrade to a 8 x 3 soon. Tank mates are 2 motoro rays. Thanks for all the input.