I have a decent sized outdoor pond that is 5 feet deep at deepest end. I currently house Koi. My UK buddies are keeping Diamond Back Sturgeon and I cant seem to find them any anywhere in the USA. Are they illegal? Do I need my CITIES to import? I live in Maryland. If these species are illegal, what species is legal to keep that stay in that 6 foot size? My pond is plenty big enough. 5000 Plus gallons. Google isn't helping at all. I'm not a forum guy. Dont bite my head off if this subject has been approached here before. I appreciate the responses. Thank you.