Captive Care Notes: Bowfins (Family Amiidae)
Bowfins are easy to keep in the home aquarium, however their tolerance for stagnant conditions in the wild does not mean they will accept such conditions in captivity. Bowfins prefer clear, clean water, and should be kept in well-filtered aquariums. Water should be soft with a pH of 6.8, although higher alkalinities (up to pH 7.5) can be tolerated. Aquarist R. W. Wolff recommends a shallow tank with dense mats of floating plants and high-intensity lighting to sustain the plant growth. Hoover and Strange (2002) report excellent growth of 25 juvenile Bowfin in an unplanted 347 l (92 gal) Ferguson flume (a rectangular tank with internally rounded corners and a central partition that allows an elliptical flow of water through the tank).
A large adult Bowfin is hard to acclimate to aquarium life unless you are prepared to feed it live fishes. Instead, it's best to start with juveniles and let them get used to captive life at an early age. Avoid small fry, however; they can be finicky eaters that ignore just about everything except live daphnia. Juveniles 3-4 inches in length can be collected year-round with a dipnet, seine, or with an unbaited minnow trap placed into a weed bed. They do well on a diet of chopped earthworms and shrimp. Eventually they'll begin to recognize you and swim to the surface in anticipation of their next meal. This is a good time to start weaning them over to prepared foods, including freeze-dried tubifex worms and shrimp pellets. As juveniles mature, Wolff likes to vary their diet. After all, Bowfins have a varied diet in the wild. He supplements prepared foods with a meaty diet of ground beef, beef heart, and beef liver, and reports excellent color and growth. Hoover and Strange (2002) caution against feeding "non-aquatic" foods such as beef liver because they are associated with juvenile mortality; instead, they conditioned their Bowfin on 1-2 feeder minnows per Bowfin once or twice a week. Be careful how much you feed, though. Bowfins can be gluttunous, eating way more than they need or can handle. As any self-respecting predator should, they will always appear hungry, but overfeeding can lead to sickness and water quality problems (which, while not dangerous to air-breathing Bowfins, are always best to avoid). Don't worry if your Bowfin hasn't eaten in a while; one forgotten aquarium specimen survived without food for an entire year! Another word of caution: Young Bowfins can be cannibalistic, with larger specimens gulping down their smaller siblings. Make sure your specimens are all roughly the same size.
Once Bowfins settle in to aquarium life, they can become tame enough to take food from your hands. Wolff notes that Bowfin are "highly social, and you will see them holding in dense weeds, stacked together like cord wood." However, other aquarists indicate that Bowfins get increasingly territorial amongst themselves as they mature, and may need to be moved to separate tanks. Not many other fishes can be kept with Bowfins, but Wolff reports good luck with gars. Be prepared for healthy, well-fed Bowfins to quickly outgrow their tanks; an overall growth rate of 0.4 mm/day has been reported (Hoover and Strange, 2002). And be prepared for a long life; one Bowfin at the New York Aquarium lived there 30 years.
At night, when they're prowling for food, larger Bowfins may dislodge filter hoses or jump out of the tank. Should a Bowfin liberate itself, don't automatically assume it is dead when you find it the next morning. The air-breathing adaptation that allows it to survive in mud may also keep it alive during an accidental visit to your fishroom floor.
There are no reports of Bowfins spawning in aquaria, probably because of their size. However, Bowfins will spawn in large outdoor ponds if vegetation is present. The only problem aquaculturists face in raising Bowfin is providing a proper diet, since Bowfins all but ignore the pelleted feeds that are commonly used at catfish and trout hatcheries. Instead, aquaculturists prepare a "wet" pellet by placing 50% carp fillet, 40% carp guts or eggs, and 10% floating catfish fingerling feed into a food processor and grinding it into a "red goo" that sticks to your fingers.
