Bowfin arent commonly kept as aquatic pets so i dont know if anyone will have any advice based on experience keeping them, however i know the fish your talking about and know that they are ravinous eaters and get quite large, Id say a two hundred gallon tank or atleast 150 gallons will be needed for the adult fish. He will probably like plants as they come from marshy planted areas of lake and streams, resist the temptation to feed him feeders all the time, every once in a while will be ok. Also im not sure how entirely legal it is to keep a wild fish. maybe you should contact the local fish and game to see. Good luck.