I have my bichirs sharing space with a 20" afrowana (african arowana). Both are from african rivers, both are air breathers, and both have a prehistoric look. Because the arowanas are filter feeders, I don't have to worry about it eating any of my smaller bichirs (although it does chase them around occasionally but the bichirs have plenty of cover). Smallest is 6" teug. I also have a 20" Ornate in the bunch and it is extremely active along with the arowana. The other bichirs are a little more reserved, but I have 7 others, all different species so they cruise a round a bit too. Also a 22" Dayii eel that only really comes fully out at night but peeks it's head out of its cave during the day. I'd recommend african Arowana but get one larger than 8-10". The smaller ones are a true challenge to rear.