Coldwater fish are considered to be those that thrive in sea temperatures between 16 and 24°C. They are typically peaceful, slow-swimming species, and their contemplation helps you feel relaxed. If you're planning to set up an aquarium with coldwater fish at home, below we recommend the most suitable specimens.
Cold Water Fish
The idea has been widely spread that it is easier to breed cold water fish than those from hot or tropical water, however, this is not entirely true. A huge number of tropical water fish are easier to maintain and the overall appearance of the aquarium will be neater (in practice) than is the case with a goldfish aquarium.
The above does not mean that a cold water aquarium is not more striking. If we stick to the costs, if it can be estimated that the installation of a cold water fish tank is much cheaper, since it will not be necessary to add heaters to the water, and the acquisition of cold water fish is not very expensive.
Before you begin, what are the fish that are considered cold water? They are those that subsist in temperatures from 10ºC to 24ºC, where the most used temperatures are those that exceed 20ºC. Many of them can exist perfectly outside, since it is usual to see specimens of koi carp, goldifish, etc., fish that we can also get in cold water aquariums.
Suitable Fish for an Aquarium
Just as it is not advisable to mix large fish with very small ones, it should also be sought that the specimens have a similar behavior. Likewise, it is essential to have a wide space and that within the variety of animals, some swim at a different level than the others to prevent them from competing for space.
If you want to install a great aquarium at home, you have to start with its planning. Will I do it for saltwater or freshwater fish? What kind of accessories will you require? What will be the most appropriate specimens for your aquarium? You will have to conceive your fish tank as a community, so you cannot be tempted to house fish randomly. There are thousands of varieties of fish and not all of them can coexist harmoniously in a community.
Prepare your aquarium
If you can afford it, it is advisable to acquire a good-sized aquarium, since the lack of space makes it difficult for the fish to interact. This will also make cleaning easier, as well as the incorporation of filters, timers for temperature regulation, lighting systems, etc.
Select the kind of water for your fish tank, salty or fresh, which must always be in optimal condition. It must be pure water, free of toxic elements that can affect the health of your fish. It is advisable to use different tests that are available on the market, primarily the pH test to determine the acidity of the water and the nitrate test to calculate the level of residues it may contain.
Choose the Most Appropriate Fish
Once you have decided on the type of water to use, the next thing is to choose the most appropriate fish for your aquarium. It is very important to keep in mind that you must select those who have similar customs and needs, so that they can coexist peacefully. It is also a good alternative to introduce live plants, since they will not only decorate your fish tank, but will also be used as a refuge by the fish and will contribute to the aquarium water.
freshwater fish
One of the fish that lends itself the most to start with your aquarium is the common goldfish since it is tireless, has a long life and has a length of about 30 centimeters. Some have many colors and are little affected by temperature change. The diet of this species is diverse and can eat fresh or frozen food. In the same family as goldfish are the beautifully blue-toned shubunkin and the double-tailed wakin.
Dojo fish, a bottom fish native to Japan, is also an excellent alternative. It is a dexterous digger with a calm demeanor, with the shape of an eel and a length of up to 20 centimeters. It resists temperature variations very well and has a mixed diet.
tropical fish
As part of the tropical fish, we can refer to the danio pearl fish, which, in addition to being very active, withstand cold water very well and have a very varied diet. They meet in groups of six and are serene in behavior, suitable for living collectively.
Danio zebra fish exhibit a purple color, and like pearl fish, they are highly resistant. They require enough space to swim and quickly adapt to coexist with other fish. The platy are yellow with a black tail, and you only have to try to have the ratio of two females for each male. Otherwise, they withstand temperature variations very well.
exotic fish
If you decide to have a saltwater aquarium, clownfish are an excellent choice, as they are highly resistant to disease, are calm, and adapt well to living with other fish. They should be kept in pairs of the same variety, which will prevent fights between them. Damselfish display similar traits to the previously mentioned species in terms of resistance to disease and temperature variations.
In addition to the above, they have a diverse diet and harmonize with a wide variety of other species. Shrimp called cleaners are red and white. By feeding on bacteria, it helps keep both the fish and the aquarium clean. They gather in groups of three or four specimens and are very active throughout the day.
Recommendations
If your aquarium is for freshwater, exotic or tropical fish, its success will be guaranteed if you maintain the care that these species require, since they are regularly similar in terms of their habits, needs and behaviors. Another important issue to keep in mind when choosing the appropriate fish for your aquarium is to incorporate species that swim at different levels within the aquarium: surface fish, mid-area fish and bottom fish. This will be of great help for their peaceful and balanced coexistence.
Types of Cold Water Fish for Aquarium
Over the years, fans of aquarium fish farming have chosen a series of cold water specimens, suitable for living perfectly in an aquarium. All these fish require to live an aquatic environment that is located in temperatures of 20º to 24ºC. Some are suitable for small fish tanks, while others will require a larger aquarium or be placed directly in a pond.
Exotic Fish For Small Aquariums
The one that we present below is a selection of cold water fish that can be introduced into a small fish tank. Not all of them will share your space, as some may be territorial, or have different habitat requirements.
goldfish, red fish
- Scientific Denomination: Carassius auratus, Cyprinus auratus
- Common name: Red fish, Goldfish, golden carp, kite fish
- Aquarium size: from 150 to 200 liters
- Quiet character
- Temperature: From 16º to 20ºC
- pH: Around 7
- Diet: Omnivores
- Length: Up to 35 centimeters
The Goldfish is that traditional red fish that we have observed in fish tanks for years. Certainly keeping it in a fish tank is extremely cruel since the space is not enough. This fish is native to Asia and is very familiar with carp, since they are both cyprinids. Red fish are more popular, however, in the market there are hundreds of mutations of all kinds, from thousands of crosses, which have given rise to species that are considered different from a commercial point of view, although they are all Goldfish .
One of its great advantages is that it does not develop as much size as carp, since in aquariums the maximum length that it can reach is about 35 centimeters. They tend to socialize and share their space with other species. An option as striking as the typical red fish is the telescope fish, a variety that is obtained from the natural choice of certain specimens.
Telescope Fish
- Scientific Name: Carassius auratus
- Common Denomination: Telescope Fish, Ojones fish, Demekin, Dragon Eye Goldifish
- Aquarium Size: 200 liters
- Quiet character
- Temperature: From 18º to 22ºC
- pH: 6 to 8
- Diet: Omnivores
- Length: Up to 20 centimeters
The Telescope Fish is a variant of the Goldfish. Within the large number of mutations that exist today, this is one of the most charming and commercialized, which is also called Demekin. What makes it particularly original are its morphological alterations, with eyes that project from its head in the form of inflated balloons, for which they also receive the nickname Ojones. Strangely, their eyesight is poor and they are not good at vying for food.
From it, another cluster of mutations has been developed, with colors that range from the typical gold, to black (one of the most requested), blue, chocolate, white, even with various colors. It is conjectured that they may have originated in China, where they were known as Dragon Eye Goldfish or Dragonfish.
shubunkin
- Scientific Name: Carassius auratus
- Common Name: Shubunkin Fish, Comet Fish, Harlequin Goldfish
- Aquarium size: from 150 to 200 liters
- Quiet character
- Temperature: From 16ºC to 20ºC
- pH: Around 7
- Diet: Omnivores
- Length: 15 to 30 centimeters
The Shubunkin is another Goldfish variant, which is particularly eye-catching due to its coloration. Result of the selection and the many crosses that have been made, we find ourselves before a specimen with a bluish background color, with black and red spots, among which other colors can be obtained, such as yellow. Available for commercialization certain varieties are available, although not all of them are easy to locate.
It is a very suitable fish to preserve in a pond, since it perfectly tolerates very low temperatures, and all kinds of water quality conditions. This does not mean that we have to neglect their care, it is just an indication that at certain times they can cope with certain parameters and water quality that are not optimal.
Rasbora Galaxy
- Scientific Name: Danio margaritatus, previously Celestichthys margaritatus
- Common Name: Galaxy Rasbora, Galaxy Microrasbora, Celestial Pearl Danio
- Aquarium Size: At least 30 liters
- Quiet character
- Temperature: From 22º to 28ºC
- pH: 6 to 7,5
- Diet: Omnivores
- Length: 1 to 1,5 centimeters
The Galaxy Rasbora is a creature that is at the limit of temperature to be considered a cold water fish. In the event that your space is shared with other cold water specimens, we must bear in mind that their minimum requirements are met.
One of the great advantages of the Danio Margaritatus is its size, which does not exceed 1,5 centimeters, so a small school can be kept in the fish tank (it is recommended to gather at least 10 specimens). This achieves a much more natural effect than when keeping a few different specimens. Regarding its attractiveness, it is unquestionable, since it is a highly esteemed fish for its metallic blue color, covered with white or yellow spots, from which it gets its name, since it appears to be covered with stars, like a galaxy.
paradise fish
- Scientific Name: Macropodus opercularis
- Common Denomination: Paradise Fish
- Aquarium Size: 80 liters
- Character: Aggressive
- Temperature: From 10º to 22ºC
- pH: 6 to 8
- Diet: Omnivores
- Length: 10 centimeters
The Paradise Fish is a splendid fish for cold water tanks, as it can withstand temperatures close to 0ºC. Obviously at home we will not go to those extremes, but it is a reference so that you can understand how resistant this fish is. Although it is not usually considered a candidate for cold water aquariums, it is one of the ornamental fish that was initially imported to Europe.
It may not usually be part of an aquarium's stock, as it's not the best host for a community aquarium, as it tends to be somewhat violent and territorial. Like carp, it's native to Asia, from regions of Vietnam and China. It's an omnivorous creature and a voracious eater, and will happily eat dry food, which we must supplement with insects and larvae.
Chinese Neon Fish
- Scientific Name: Tanichthys albonubes
- Common Name: Chinese Neon
- Aquarium Size: 40 liters
- Quiet character
- Temperature: From 18º to 22º
- pH: 6 to 8,5
- Diet: Omnivores
- Length: 4 to 6 centimeters
The Chinese Neon Fish, which is known as the White Cloud Mountain fish, is a creature of usual presence in cold water aquariums, since its care is very simple and it also exhibits attractive and bright colors: greenish brown body , crossed lengthwise by a yellow line, culminating in yellow and red fins. They are rather modest creatures (4 to 6 centimeters), when compared to other cold water specimens for aquariums, such as carp or goldfish.
They are perfect for a small aquarium, which do not require much maintenance. It is a very sociable and gregarious fish that likes to live in small groups of 8 to 10 specimens, and will share its space without any problems with other varieties that can withstand temperatures between 18ºC and 22ºC. A peculiarity of this fish is that it loves to jump, so we have to cover the aquarium well, to prevent any type of unwanted mishap.
siamese fighting fish
- Scientific Name: Betta Splendens
- Common Name: Siam Fighter
- Aquarium size: from 20 to 40 liters
- Character: Aggressive and Territorial
- Temperature: From 24º to 28º
- pH: 6,7 to 7,5
- Diet: Omnivores
- Length: 6,5 centimeters
Despite the fact that they are native to tropical waters, Betta Splendens show great resistance and are optimally suited to cold water aquariums. However, it has a fairly short life expectancy, between 2 and 3 years. His common denomination "Fighter of Siam" is an obvious allusion to his territorial and violent nature. They are not fish adapted to sharing the aquarium with other male specimens, but they usually live very well in small groups, with two or three females.
The care of the Betta Splendens is relatively simple, but we must pay particular attention to its diet. In addition to the commercial formulas designed for their nutrition, it is convenient to add living beings to their diet: water fleas, eggs, worms, etc.
Large Fish for Large Format Aquariums
Certain cold water fish cannot survive in a traditional aquarium, they require a large space. They are large cold water creatures that cannot thrive in a 200 liter aquarium, so they will regularly require a much larger cold water tank:
Koi Carp Fish
- Scientific Name: Cyprinus Carpio
- Common Name: Carp Fish, Koi Fish, Koi Carp
- Aquarium Size: 200 liters
- Quiet character
- Temperature: From 17º to 24ºC
- pH: 6,8 to 8,5
- Diet: Omnivores
- Length: Up to 90 centimeters
The Koi Carp is one of the fish with the greatest presence on the planet, and one of the most frequent in ponds and cold water tanks, since it can be raised outdoors. He is directly familiar with the common carp, since it is certainly a variety that originates from the crossing of different carp, until obtaining what is known today as the Koi Carp. Although the origin of the Koi Carp hatchlings is in China, it is thanks to Japan that their popularity throughout the world is due.
The most problematic thing that can be presented to us with aquarium carp is the immense size that they can achieve. Although it is not so easy for them to fully develop in a fish tank, theoretically they could reach a length of two meters, but the usual thing is that they measure just over 75 centimeters. Due to their enormous voracity, it is not easy for them to coexist with other fish, since they could serve as food.
Their diet is omnivorous, eating invertebrates, algae, crustaceans, other fish, seaweed, and plants. Therefore, they are easy to care for, as they can be fed prepared foods, supplementing their diet with all kinds of home-grown vegetables, such as lettuce, peas, etc.
percasol
- Scientific Name: Lepomis gibbosus
- Common Denomination: Percasol, Perca Sol, Pez Sol, Pez Calabaza
- Aquarium Size: 200 liters
- Character: Pacific. Territory in breeding season
- Temperature: From 4º to 22º
- pH: 7 to 7,5
- Diet: Carnivore
- Length: 10 to 20 centimeters
Although they rarely exceed 20 centimeters in length in a pond or aquarium, these creatures can reach a length of 40 centimeters in the wild. They are not fish that enjoy sharing their space with smaller fish, as they are essentially carnivores, and any small fish is "part of their diet." If we are going to add them to an aquarium, it should be at least 200 liters or larger.
Certain vegetation will have to be available, which is the habitat in which they are comfortable. In terms of water quality, they are "survival" fish, they have the ability to survive in poor quality water. Obviously it is not going to be the condition that we are going to facilitate, but with it we will know how resistant this variety of cold water fish is.
Lizard peje
- Scientific Name: Lepisosteus oculatus
- Common Denomination: Garbage gar, Ocellated gar, Painted gar, Painted gar, Painted gar, Alligator fish
- Aquarium Size: From 600 to 1000 liters
- Character: Pacific
- Temperature: From 12ºC to 20ºC
- pH: 5 to 7,5
- Diet: Carnivore
- Length: 125 centimeters
The alligator gar is a unique creature, whose origins date back to human prehistory, which is why they are classified as "survivors". It has an elongated body in which the body, head and mouth cannot be differentiated. Precisely because of their mouth, full of threatening conical teeth, they have been given the nickname "alligator fish". It is not a variety that can coexist with small fish, since, as happens with species of this class, they would become part of their diet. However, it is a very sociable fish, in the meantime do not settle for part of its dinner.
Requirements for a Cold Water Aquarium
Installing a cold water fish tank is not far from having any other type of aquarium, but it is convenient to consider the elements that are essential for the fish to be in perfect condition:
Filter
Filters are an essential component in any aquarium, since thanks to the filters we can control the quality of the water. A disproportionate increase in nitrites/nitrates could be dangerous for the existence of fish. Subject to the size of the aquarium, the number and variety of fish, the filter must have the capacity to purify a defined number of liters of water.
Automotive Lighting
The lighting of the aquarium should not be neglected, which must be appropriate to the species that reside within it. Aquarium lights are not a simple decoration, they have a lot of relevance in the life inside the tank, particularly if added to the fish we add plants, which are essential inside a cold water fish aquarium, not only because they simulate their original environment , but because they also help the filtering process.
Aquarium Heater or Fan
Although we are talking about cold water fish, which in most cases will not require a heater, they will also depend on an adequate ambient temperature inside the house. Evaluate whether you need a heater or a cooler, or perhaps both, since it is of the utmost importance that the temperature of the water is appropriate.
Aquarium plants
Plants are another required component, it could be said that they are indispensable within the aquarium, but the need to incorporate them or not will depend on the diversity of fish with which you plan to set up the aquarium. Certain fish feed on the soft leaves while others extract the plants. There are plants that fit any circumstance, you just have to choose them.
Substratum
Substrate is required for both plants and fish, although primarily for the former. Fish can subsist perfectly on an inert substrate, made up of sand or gravel, but growing plants requires that the substrate provide nutrients and support for the roots.
Aquarium fish
Finally, choose the fish that will be part of the tank. You must have taken the precaution of having previously cycled the aquarium, so that the water condition is the best. As for the fish, you must check that the selected species are compatible
You must ensure that they share similar water qualities and temperatures, that the aquarium is suitable for them to live in a similar environment, etc. It is recommended not to introduce tropical fish with cold-water fish, and likewise, you cannot overpopulate the aquarium. It is not necessary to have 10 different species of fish for the aquarium to be successful..
How to care for cold water fish
Cold water aquarium fish are easy to maintain in water at room temperature, which can tolerate variations in the temperature of the water where they reside. This is the biggest difference they have with tropical fish, which require aquariums in which the temperature conditions of their original sites can be replicated.
From a general point of view, cold water fish have great resistance. Surely more than one pond is known in which carp subsist throughout the year enduring very low temperatures. It's not going to be a home aquarium situation, but it helps to illustrate just how resilient these fish are. Follow these suggestions, so you can install your cold water aquarium without any inconvenience:
- Prior to the introduction of various species in a community aquarium, it is advisable to ensure how compatible they are. If you have any questions, you can consult the store's salesperson.
- You must permanently monitor the health of the aquarium fish. That fish that is remote and does not participate with the others, any fish that alters its color or that is attacked by the rest, without apparent cause, is a fish with some discomfort. It is convenient then to separate it, until recognizing that it happens to him. Consult a specialist to assess the appropriate treatment.
- Within the group of Goldfish we have highlighted the case of the Telescope Fish, which has problems seeing correctly, which causes problems when it comes to competing for food. This circumstance is not unique to this fish. If you know of a fish with particular needs, ensure that they are taken care of, so that they do not evolve into a major problem.
Cold Water Fish Food
Until now we have made reference to the requirements for the installation of an aquarium, so that cold water fish are at home. We have also defined which species are the most appropriate according to the size of the tank. Something that we cannot forget is the diet of the fish, on which much of the good health of aquarium specimens is based.
A counterproductive or incomplete diet could cause the onset of diseases. The following are the foods that you can supply to cold water fish:
- dry food. Dry food for cold water fish is available in all kinds of presentations: flakes, sticks, granules (the most appropriate for automatic dispensers). There is a huge variety, since manufacturers have designed complete foods, which can be used as the only food, or as a supplement to another based on live foods.
- live food. Artemias, worms, tubifex, daphnia, the easiest to obtain is artemia, from which we can make a simple hatchery at home.
- frozen food. All insects noted above, but frozen for storage.
- fresh food. Numerous fish need to supplement their diet with fresh food, among which we will incorporate peas, lettuce and all kinds of leafy vegetables.
It is important to keep the amount of food we supply under control, since a surplus of food will result in greater dirt in the fish tank, decomposition and an increase in nitrites. He can cause the aquarium parameters to go out of control, so it is convenient for us to only supply them with the food that they are capable of gobbling in a few minutes.
Origin of Cold Water Fish
Obviously cold water fish come from cooler climates than hot water fish, coming mostly from Europe, the United States and North China. They are creatures that manage to subsist perfectly in temperatures that do not exceed 15ºC, and certain specimens such as carp have been seen to enjoy themselves in open-air ponds, tolerating temperatures of 10ºC.
Perhaps the most notorious representative of cold water aquariums is the Goldfish, the variety of fish for cold water tanks that has been bred in China for more than 2.500 years. Fish like this, which have been bred for a long time, have given rise to a selective breeding of fish with different appearances, colors and fins.
Aquarium Considerations for Cold Water Fish
A question that one should ask before choosing cold water fish for our fish tank, is what size will they reach in their adulthood? The fish that can be obtained in pet stores are babies and apparently small. Certain varieties grow quite large and it is convenient to have an aquarium suitable for their size. It may happen that the aquarium is not suitable for the size of the selected fish, in such cases the fish usually have development and health problems, while those that do not have a good adaptation may perish from stress.
Goldfish eat abundantly and evacuate just as forcefully. This particularity about their diet and life habits, requires us to choose an appropriate filtering system. Another issue to keep in mind is the lighting, which must be balanced to prevent the emergence of algae in an uncontrolled way. In tropical fish tanks with warm water fish, this issue is solved by including some species that feed on algae, but it is not so simple when we refer to cold water fish.
The plants that can or should be included in a cold water fish tank must have a lot of resistance. Sometimes goldfish tend to feed on leaves, so you have to choose species that, in addition to being resistant, can develop in environments with poor lighting.
Other articles that are part of our recommendation are:
- Ichthyology
- Aquatic animals
- Domestic animals