A heater is necessary for aquariums, right? But it is not completely. Have you ever heard of cold water fish? This is one species that does not need a heater. In this article, we will cover 9 cold water fish for your aquariums and how to take care of cold water fish. Hope you will enjoy reading it!
What are cold-water fish in aquariums?
Cold water fish are species that can keep alive without heaters in aquariums. Most of them can thrive in temps of 60-65℉. Generally speaking, a lot of cold-water fish can not accept warm water, as a result, much cold water fish in tanks should be kept in species-only aquariums. And about the lifespan of cold-water fish, depends on their species. But normally they can live for about 5 years.
9 popular cold water fish for your aquariums
Next, let’s learn 9 cold water fish for your aquariums. Hope you will get your favorite one! Fish will be covered as follows:
| Rosy Red Minnow | Paradise Fish | Veiltail Goldfish |
| Goldfish | Rhodeus | Eucyclogobius Newberryi |
| White Cloud Mountain Minnow | Asian Stone Catfish | Bloodfin Tetra |
1. Goldfish
Goldfish are active and hardy. It is better not to keep them with small fish for their voracious appetites. There are many breeds of goldfish, including Veiltails, Shubunkins, Fantails, and others.
| Scientific name | Carassius auratus |
 Goldfish |
| Origin | China | |
| Diet | Omnivore | |
| Size | 5-10 inches | |
| Minimum tank size | 50 gallons | |
| Water temp | 60-72℉ |
If you want to know how to determine the gender of goldfish, you can read this article – How to Know If a Fish Is Male or Female.
2. White Cloud Mountain Minnow
White cloud mountain minnows are one of the best cold water fish in aquariums. They are peaceful and easy to care for. Besides, they prefer cooler water temps. If you need tank mates with peaceful fish, the white cloud mountain minnows are a perfect option. Besides, they are in different colors – gold, silver, and albino.
The white cloud mountain is given the name because of the White Cloud Mountain in China, where they live in the wild.
| Scientific name | Tanichthys albonubes |
 White Cloud Mountain Minnow |
| Origin | China | |
| Diet | Carnivore | |
| Size | 1.5 inches | |
| Minimum tank size | 10 gallons | |
| Water temp | 58-72℉ |
3. Rosy Red Minnow
Rosy red minnows are peaceful and perfect for cold water aquariums. But they are usually used as bait and feeder fish. Besides, they can be kept in a wide range of temperatures. And they can live for 2–4 years on average. Moreover, they are easy to care for, and they are adaptable to thrive in a wide range of water conditions. But it is also necessary to pay attention to their needs and keep the living environment comfortable.
| Scientific name | Pimephales promelas |
 Rosy Red Minnow |
| Origin | USA, Mexico, Canada | |
| Diet | Omnivore | |
| Size | 2-4 inches | |
| Minimum tank size | 15 gallons | |
| Water temp | 50-78℉ |
4. Asian Stone Catfish
Asian stone catfish are peaceful and nocturnal fish. It is better to feed them at night. Besides, they are suitable for unheated tanks. They can be kept with tank mates, are small and peaceful.
| Scientific name | Hara jerdoni |
 Asian Stone Catfish |
| Origin | India, Bangladesh | |
| Diet | Carnivore | |
| Size | 2 inches | |
| Minimum tank size | 10 gallons | |
| Water temp | 64-75℉ |
5. Rhodeus
Rhodeus can live for about five years. They prefer slow-flowing or still waters because they rely on freshwater mussels to reproduce. They are not only ornamental fish but also with medicinal value. Moreover, algae are the main food for Rhodeus.
| Scientific name | Rhodeus |
 Rhodeus |
| Origin | Asia and Europe | |
| Diet | Omnivorous | |
| Size | 4 inches | |
| Minimum tank size | 10 gallons | |
| Water temp | 55-71℉ |
6. Paradise Fish
Paradise fish are easy to care for and semi-aggressive. They are famous as the Chinese fighting fish and the paradise gouramis. Besides, they enjoy living in unheated aquariums. Moreover, it is recommended to keep them in a quarantine tank before introducing them to an aquarium.
| Scientific name | Macropodus opercularis |
 Paradise Fish |
| Origin | South and East Asia | |
| Diet | Carnivore | |
| Size | 3 inches | |
| Minimum tank size | 20 gallons | |
| Water temp | 50-71℉ |
7. Veiltail Goldfish
Veiltail goldfish are peaceful and can be tank mates with other goldfish. They have extra-long, flowing double tails and high sail-like dorsal fins. But their tails are easy to be damaged. Besides, Veiltail would be impacted by low water temperatures. As a result, they are hard to care for.
| Scientific name | Carassius auratus |
 Veiltail Goldfish |
| Origin | United States | |
| Diet | Omnivore | |
| Size | 8–12 inches | |
| Minimum tank size | 20 gallons | |
| Water temp | 65-72℉ |
8. Eucyclogobius Newberryi
Eucyclogobius newberryi is also called the Northern Tidewater goby. They are easy to keep and suitable for beginners. Besides, they are with a short life span of about 2–3 years. One kind in Australia just lives for only 59 days. Of course, the fish can grow fast too, they can mature within 3 weeks, then die after mating and laying eggs.
| Scientific name | Eucyclogobius newberryi |
 Eucyclogobius Newberryi |
| Origin | United States and California | |
| Diet | Carnivore | |
| Size | 2 inches | |
| Minimum tank size | 10 gallons | |
| Water temp | 46-87℉ |
9. Bloodfin Tetra
Bloodfin tetras have blood-red fins, which gives them a striking appearance. Besides, they are semi-aggressive. Moreover, they are hardy fish, so they can adapt to a wide range of water temp. And they can live for over 5 years.
| Scientific name | Aphyocharax anisitsi |
 Bloodfin Tetra |
| Origin | Brazil, Argentina, Paraguay | |
| Diet | Carnivore | |
| Size | 2-3 inches | |
| Minimum tank size | 15 gallons | |
| Water temp | 64-82℉ |
How to take care of cold water fish?
At present, we have shared 9 cold water fish for your aquariums. But how to take care of them? Do not worry, there are tips for you!
Tank setting
A large tank is suitable for cold-water fish. However, the number of fish determines the size of your aquarium. Before introducing your fish into new tanks, it is better to cycle your tank for at least one week. It will ensure that the water is clean and allows for the formation of good bacteria. Besides, a fish tank filter and aquarium thermometer are needed.
Cleaning
Changer the water regularly. You can remove 25 percent of the water at a time. Besides, you can use a gravel cleaner to remove unnecessary floating debris.
Feeding
Do not overfeed. You can feed them foods that they can finish eating within 4–5 minutes. And you can feed them 2-3 in one day. If there are different species in a tank, you may need to feed various kinds of food to meet their requirements.
Tank mates
If you keep the incompatible fish in a tank, it will cause disease and injury. It is better to do research before selecting tank mates. For example, species, including goldfish, danios, and blood fin tetras, are compatible tank mates.
Health care
It is necessary to check your fish once a day. Before introducing new fish, you should make sure that they are healthy.
Fungal infections and internal parasites are common diseases for cold-water fish. You should pay attention to the physical changes, including changes in color, spots, bulging eyes, and swelling. These are signals of disease. Once noticed, it is better to get treated as soon as possible, or other fish in tanks could be infected.
Conclusion
Until now, we hope you have learned more about cold water fish and how to take care of them.
By the way, there are some advantages to keeping cold water fish.
- Cheaper: you do not need to buy a heater.
- Fewer Algae: Algae prefer warm water.
- Less maintenance: no need to worry about water temps.
That’s all for today, thank you for your reading!
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