Canada

The bowfin, Amia calva, is the sole remaining member of the family Amiidae, from south-eastern Canada and the north-eastern USA. It breathes atmospheric air through a highly vascularised organ and can aestivate in wet ground during drought. A temperate predator growing to around 900 mm, it needs a very large tank of its own, and its sharp teeth and readiness to bite make it a dangerous species to own. Captive specimens over 30 years old are known.

The grass carp, Ctenopharyngodon idella, is a large cyprinid native to the Amur River system in eastern Russia and northeastern China. Adults typically reach 800 to 1200 mm, making it a wholly unsuitable aquarium subject, though an albino form is traded. Widely introduced for aquaculture and weed control, it has caused serious damage to natural waters, and unwanted fish should never be released.