Rosy red minnows are feeder fish. Feeder fish are primarily used as food for larger species, and they are bred specifically for that purpose. However, these pretty, active little fish can make a good addition to a tropical display tank too.
In this article, we look beyond the minnows’ unfortunate fate as a fast-food item and discuss how these fish could make the perfect starter specimen for a beginner hobbyist’s home aquarium.
What is a Rosy Red minnow
The Rosy Red minnow is also known as the Fathead minnow and has the scientific name, Pimephales promelas.
These fish grow to measure around two inches in length, making them ideal for life in a small tank. Red minnows are actually a color variant of the native Fathead minnow whose natural coloring is primarily metallic silver, with dark horizontal stripes that appear during the spawning season. In contrast, Rosy Red minnows are bright, metallic orange in color with a dusky patch on their dorsal fin.
The Rosy Red minnow is often sold primarily as a feeder fish in fish stores. However, a small school of these pretty fish makes a great addition to the midwater region of a display tank, and by giving a safe home to a few of these guys, you’ll get to enjoy a warm, fuzzy feeling of a few lives saved too!
If properly cared for and given the right diet, Rosy Red minnows can live for up to two years. That may not seem like much of a lifespan, but these little fish are very readily available and inexpensive, so if you do end up replacing your minnows every couple of years, that should not be a problem. Also, minnows breed very easily with little or no intervention from their owners, so you may even find that you never need to buy another fish once you’ve invested in your first batch.
Origins and natural habitat
The wild Fathead minnow is found throughout much of North America, ranging from central Canada, along the Rockies as far as Texas, and to the east into Virginia and the northeastern U.S.
Pimephales promelas are extremely tolerant of different water conditions, helping to account for their wide distribution. These fish can live in low-oxygen water, commonly being found in ponds, wetlands, and small lakes, although they can also live happily in streams and larger bodies of fresh water where the flow is stronger.
The Fathead minnow is omnivorous, sifting through the substrate to find small crustaceans, insects, aquatic invertebrates, and zooplankton. The fish also eat phytoplankton, algae, and general detritus that drifts to the bottom of the habitat.
Rosy Red minnows are ostariophysan fishes and produce what’s known as Schreckstoff.
Schreckstoff is an alarm substance that is released when the fish’s epidermal club cells are damaged following an attack by a predator. The signal can be detected by other ostariophysan fish, warning them of danger and triggering antipredator behaviors such as darting away or hiding.
When the alarm substance is ingested by a predator, it will chemically label that creature as presenting a danger to the minnows. So, when in areas where the visibility is poor, the Red minnows can quickly detect ambush predators, such as Northern pike, and make good their escape.
Care of the Rosy Red minnow
In this part of our guide, we explain how to care for these glittering fish that can make a very attractive addition to the home aquarium.
In theory, you could keep a small group of minnows in a five-gallon tank, although a larger aquarium is recommended. If you are planning on keeping a school of ten Rosy Reds, the tank size should be at least ten gallons.
Rosy Red minnows can live in a wide range of water temperatures from 320 right up to 1000 Fahrenheit, making them ideal for all freshwater tanks, including coldwater setups. However, the Rosy Reds’ preferred water temperature is between 700 and 800 Fahrenheit, and the fish will spawn pretty much continuously if kept at these temperatures.
Minnows can cope with a wide range of water conditions from mildly soft to very hard, and a broad pH range of 6.0 to 8.0.
The Fathead minnow isn’t a particularly messy fish, and most standard filtration systems will be adequate for these fish’s needs. You can use a HOB (hang-on-back) filter if you want to, although a sponge filter will keep the tank clean and properly filtered. Of the two options, a sponge filter is probably the best choice, as it keeps the tank well-aerated and is much safer for the Rosy Red minnows’ fry.
If you do opt for a HOB filter system, you should cover the intake with a piece of nylon or a sponge to prevent the fry from being sucked into the impeller.
Male Rosy Reds can become quite territorial once they reach breeding age, so it’s essential that you provide plenty of caves, rocky overhangs, and floating plants for them. Each male fish will claim a small territory and defend it vigorously, so the larger the tank is, the better, especially if you are planning on keeping a single-species setup.
If you don’t want to buy resin caves, you can take a plain, unpainted clay pot, and set it on its side, partially buried within the substrate to create the perfect cave.
Also, it’s a good idea to include plants in your tank. The fish like to explore the plants and scavenge for scraps of food that have dropped onto the leaves from above. Also, you could include some driftwood that will encourage the growth of algae, providing a source of food for the minnows.
Diet and nutrition
In the wild environment, the Rosy Red minnow is omnivorous, eating plant matter, algae, insect larvae, tiny crustaceans, and invertebrates that it filters from the bottom of its habitat.
You may find that your tank-kept Pimephales promelas prefer more in the way of plant-based foods, happily taking a high-quality pellet or spirulina flake. It’s also a good idea to provide your minnows with an occasional treat of frozen bloodworms, brine shrimp, or daphnia. Note that these foods should be offered sparingly, and the minnows’ diet should consist primarily of herbivore fish food.
Rosy Reds enjoy freshly blanched vegetables, such as cucumber, shelled peas, and cucumber, which you can cut into medallions and add to the aquarium. Be sure to remove any uneaten food after 24 hours so that the water doesn’t become fouled as the veggies decompose.
Minnows are peaceful schooling fish that are happiest when kept in groups of adult pairs of up to ten fish.
The Rosy Red is a hardy fish that gets on well with any small, peaceful species. Minnows inhabit the mid-water range and enjoy plenty of swimming space. So, choose tank mates that tend to stay in the bottom area of the tank, such as Corydoras catfish. Tetras get on fine with minnows, as do Gouramis.
Although you can keep minnows with goldfish, as they share the same water parameter preferences, be very careful that you don’t put them in with fancy goldfish varieties that can grow large enough to view the minnows as dinner. The same goes for any large species of omnivorous, potentially predatory fish.
Snails and shrimp make good tankmates for the Rosy Red minnow too.
Pimephales promelas are incredibly easy to breed, making them the perfect starter project for newbies to the hobby. Indeed, many people raise this species as feeder fish for their predatory fish to feed on, preferring to offer food that they know is healthy.
One particularly fascinating aspect of keeping the Red minnow as an aquarium fish is their extraordinary breeding behavior. Most species of minnows simply scatter their eggs and play no parental part in raising the fry. However, Rosy Reds’ behavior is more on a par with that of cichlids.
To encourage spawning in minnows, you need to provide a photoperiod of between 12 and 14 hours each day and maintain the water temperature in a constant 700 to 800 Fahrenheit range.
The lengthened “daylight” and warmer water helps to replicate the conditions that trigger spawning in wild Rosy Reds and usually gets things going in the tank environment.
Once the male is in breeding condition, he will develop breeding tubercules and fatty tissue on the top of his head. That’s what gives the species its other common name, “Fathead.”
When the male is ready to mate, he will claim an overhang or cave and clean the surface thoroughly with his head. At this time, other males will try to challenge the male for his patch. Although fights can appear alarming, they are generally very brief and rarely result in fatalities or serious injuries.
Once the male’s territory is secure, he will try to entice a female into his carefully prepared breeding cave. You’ll be captivated by the intricate courtship dance that begins, as the male tries to tempt the female. If she’s suitably impressed, the female will follow the male back to the cave where she deposits her eggs. Once the eggs have been laid, the male usually chases the female out of the cave and begins fiercely guarding the precious eggs.
Nurturing the eggs and fry
The male Rosy Red minnow remains in his cave, watching over his clutch of eggs. He will rub his head and snout over the eggs occasionally, depositing an anti-fungal solution on the eggs to keep them free-from disease as they develop.
You may notice other females entering the cave and depositing their eggs until the walls are completely covered. The male will continue guarding all the eggs until they hatch, attacking any fish that comes close to his “family,” regardless of the interloper’s size.
After a few days, the eggs will begin to hatch, and you will see free-swimming fry beginning to appear. At that point, you will need to feed the fry with micro-worms or baby brine shrimp. You can also offer the fry powdered spirulina, which they will eat.
When all the eggs have hatched, and the fry is safely free-swimming, the male usually abandons his cave. Don’t worry; the fry won’t become food for their parents, as adult Rosy Red minnows very rarely eat their young.
Diseases and health
The Rosy Red minnow is actually a pretty healthy and robust fish. The biggest challenge is finding healthy specimens. Most feeder tanks in fish stores are full of diseases and parasites, and the water quality is awful.
For that reason, you must never put Rosy Reds directly into a tank that contains other fish, as you risk infecting the whole of your community. So, place your new fish into a quarantine tank for at least four weeks. During that time, you should treat the tank routinely for disease and parasites, as well as making sure that the fish appear healthy and are eating well. Even taking that sensible, precautionary approach, you can still lose a few fish. Stunted growth and deformities are also not uncommonly seen in rescued feeder fish.
That said, Pimephales promelas breed extremely quickly, and you will find that the next generation that is born in your tank will most likely be larger and show much better coloration than their parents.
Unfortunately, the only place you can usually find Rosy Red minnows is in the feeder fish tank in most fish stores.
Often these tanks are cramped and dirty, so the fish may not be the healthiest specimens. However, Rosy Red minnows are hardy fish that can survive in a variety of conditions, and there will be some healthy ones in there if you look hard enough.
The upside of the fish’s predicament is that they are inexpensive to buy at just a few dollars for a small group of fish.
In this section of our guide, we answer a few of the most commonly asked questions that people have when considering offering a safe haven to a school of these attractive, lively fish.
Q: How big do Rosy Red minnows get?
A: The Rosy Red minnow grows to around two inches in length.
Q: How long do Rosy Red minnows live?
A: Minnows generally live for around two years if given the correct diet and living conditions.
Q: Are Rosy Red minnows aggressive?
A: No. The Rosy Red minnow is a peaceful schooling fish that gets on very well with other species of a similar size and temperament.
Q: How much do Rosy Red minnows cost?
A: Rosy Reds and other feeder fish are generally sold in bulk lots of 20 fish for around $10, although the price does vary considerably, depending on the supplier. If you want to buy ten minnows to add to your display tank, you should expect to pay around $5 or $6.
Rosy Red minnows are usually sold as feeder fish that are destined to become fast-food for large predatory species. However, these pretty little fish can also make a great addition to the display aquarium.
Minnows are super-easy to keep, are tolerant of a wide range of water conditions and temperature, and are very hardy, disease-resistant characters, so these attractive, lively fish can make the ideal starter fish the beginner hobbyists.