The only downside to these fish is that, since they are sold as "feeder fish" or "bait," they usually have parasites and other health problems due to overcrowding and poor care. Medications and good care can reverse this. Pick apparently healthy fish with which to begin.
Rosy red minnows and sometimes fathead minnows are being more frequently added to ponds. They are added as dither fish to make larger fish (koi and goldfish) less cautious and more active.
They are added to provide movement during the winter when larger fish are resting (rosy reds like to cruise under the ice). They are added when the pond is simply too small for larger goldfish or koi.
They live up to 3 years of age.
Rosy Red & Fathead Minnows
Common names: rosy red minnow, fathead minnow, rosy reds, rosey reds, rosies, tuffy, tuffies, blackhead minnow, tuffy minnow, rosy red feeders, ruby red feeders, red top minnows
Characteristics - dark olive above with coppery tinge behind head and along sides, sides silvery and belly white; back broad and flat in front of dorsal fin; dusky band or blotch in front and rear rays of dorsal fin; maximum length of about 3 inches.
Fathead minnows spawn from early May through August. The adhesive eggs are deposited on the under surface of floating objects, and the male guards them. The eggs hatch in 5 to 6 days.
They will not harm any fish (except small fry when they are hungry).
They are so prolific breeders yet their breeding is easy to control if you do not want fry. In a pond, natural predators (frogs, orfes, snakes, turtles) keep them in check while also distracting predators from eating your other species of fish.
They can survive from right above freezing to the 90's (degrees Fahrenheit).
They make excellent pond fish.
They are inexpensive, typically one dollar for a dozen.