Minimum Tank Size: 5 Gallons (10 Gallons recommended)
Care Level: Very Easy
Water Conditions: PH 6-8 and Soft to Very Hard
Temperature: 32-100 (0-37C)
Maximum Size: 2 inches (5 cm)
The rosy red minnow is normally sold as a tropical fish, but it is actually a color variant of a native North American fish – the fathead minnow. The fathead minnow is found throughout streams and rivers in North America, and its natural coloring is a brilliant silver, with the males developing dark horizontal stripes during mating season.
If someone is looking to purchase a rosy red minnow, the only place that they can normally be found are the cramped and filthy feeder tanks at most fish stores. But if you can find some healthy ones, they make an attractive and interesting addition to nearly any community fish tank.
The same qualities that make rosy red minnows great feeder fish, also make it one of the easiest fish to keep. It can be kept in densities that would kill any other tropical fish and tolerates both poor water quality and low oxygen levels in an aquarium. In the stores you will often see hundreds or even thousands crammed together with little in the way of water circulation and many will still be active and healthy after living in these wretched conditions.
Rosy red minnows can also tolerate a wide range of water types – from mildly soft to very hard water and a pH range of 6pH – 8 pH. These hardy minnow will also adapt to nearly any temperature, with reports of it thriving at temperatures below freezing, and in temperatures as high as 100F (37C). It prefers temperatures in the range of 70-80F (21-26C), and will breed continuously if it is kept at these temperatures.
If you are planning to keep rosy red minnows in a species only tank, a 10 gallon tank is the preferred size. It is important that you provide a few cave like structures or overhangs in their tanks. Once the males hit breeding age, they will claim a cave and defend it against any other males rosy reds or other fish in the tank. The easiest way to provide a cave, is to purchase a plain, unpainted clay pots, and then partially bury them on their side in the substrate. This creates a perfect cave environment for rosy red minnows.
The rosy red minnow generally isn’t a messy fish, and most types of filtration will be more than adequate. A good HOB (Hang on back) filter, or sponge filter will keep the tank clean and well filtered (Click here for HOB filter reviews). With that being said, the sponge filter is usually a better choice, as it provides good aeration for the tank and is far safer for the fry that are certain to appear at some point. If you choose to use a HOB filter, you should use something (nylon, sponge) to cover the intake, or the fry will be sucked up into the whirring impeller of death.
In the wild, the rosy red minnow is an omnivore, and eats algae, plant matter, small invertebrates and insect larvae. In the home aquarium, they seem to prefer plant based foods, and if you are having trouble keeping rosy red minnows well fed, they should be fed a high quality spirulina flake of pellet food.
They will also appreciate the occasional treat of frozen foods, and can be feed frozen bloodworms, daphnia and brine shrimp. These should be fed sparingly, and their main diet should be a herbivore fish food.
A rosy red minnow’s diet can also be supplemented with vegetables, with blanched zucchini medallions, cucumber medallions and shelled peas being their favorites.
One of the most compelling reasons to buy rosy red minnows is to experience their fascinated breeding behavior. While most minnows scatter their eggs and show no parental care, the rosy red minnow breeding behavior closely resembles a cichlids. In fact, rosy red minnows are probably the easiest fish to breed in the aquarium hobby, and many people with predator fish breed rosy red minnows to ensure they have healthy feeder fish.
In order to trigger breeding in this fish, you should provide a photo period of 12-14 hours a day and keep the temperature constant in the 70-80F range. When the male is ready to breed, he will develop fatty tissue and breeding tubercles on the top his head (thus the name fathead). Once he is ready to mate, he will claim a cave or overhang in the tank and clean the surface thoroughly with his head. Other males that are ready to breed may challenge the male for his newly claimed territory, but any fights are generally brief and rarely result in injuries.
After the male has successfully fought off any challengers, he will attempt to entice a female into the cave or overhang. An intricate dance will commence between the two fish, and if the male impresses the female, he will lead her back to the cave and she will deposit her eggs. The female is then usually pushed out by the male, and he seta about fiercely guarding the eggs.
The male will watch over the eggs carefully, occasionally rubbing them with his head and snout which contains an anti-fungal solution. Other females may sometimes be enticed into his cave until the walls of the cave are completely filled with eggs. The male will guard the eggs until they hatch, and he will attack fish many times his size to protect his brood.
After a short period, the eggs will begin to hatch, and free swimming fry will appear. At this point, they should be fed with mircoworms, or baby brine shrimp. Another effective, but unorthodox method for feeding the fry is to feed them powdered Spiraluna. Once all of the eggs have hatched, the male will usually abandon his cave, and will ignore the fry. In most cases it’s safe to leave the fry in the same tank as adult rosy red minnows, as they rarely eat their young.
Rosy Red Minnow Health
The most difficult aspect of keeping rosy red minnows, is actually finding healthy ones. The feeder fish tanks at most fish stores are full of parasites, diseases and have absolutely terrible water quality. Rosy reds should never be put into an aquarium containing other fish, until they have been quarantined for a minimum of four weeks in separate quarantine tank and treated for parasites and disease.
Even taking this approach, quite a few will die since they are already likely ill from living in a feeder tank. Some may also end up stunted and eventually deformed from the parasites that they have been infected with. But rosy red minnows breed very quickly, and the next generation that is born in the home aquarium will have much better coloration and size than their parents. So just stick it out, and you will end up with some amazing rosy red minnows.