30 Best Cold Water Fish For Your Aquarium (June 2024)

Many people choose to populate their fish tank with a variety of freshwater fish or cold water fish. Depending on your location, certain types of cold-water fish will do better in your aquarium than others.

Many prefer these types because they can live in a community with a wide range of other fish that come from all different locations and climates.

To get the most enjoyment out of your cold-water fish, you should make sure that they are compatible with each other. You also need to make sure that the tank is set up correctly before putting anything in it. You can also add decoratives and plants like Ludwigia Repens.

The Best Cold Water Fish For Your Aquarium

The list below will give you 30 of the best cold-water fishes for aquariums.

White Cloud Mountain Minnow

Scientific Name: Tanichthys albonubes
Size: 2 to 3 inches
Lifespan: 3 to 5 years
Nature: Active, beautiful and aggressive
Water Temperature: 60 to 65 degrees Fahrenheit.
ph level: 6.0 to 7.5
Required Tank Size: 10 to 12 galloons
Required Water Type: Highly Oxygenated water conditions

These fish are actually not a type of minnow at all and originate from Southwestern China. They can grow between 2-3 inches long, and their body is silver with a black stripe running along the length of it.

They also require a pH level of 6.0 to 7.5. These fish are from the Yunnan Province in China, and they are popular because of their color pattern.

They have light grey bodies with darker grey spots on them, and they also have a black tail fin with 2 white dots near the tip.

These fish are very small, so you can keep up to 6 of them in a 10-gallon tank, but it will require some patience when it comes to their breeding.

These fish are considered cold water fishes, but they are more comfortable in temperatures between 60 and 65 degrees Fahrenheit.

Zebra Danio

Scientific Name: Danio rerio
Size: 2.75 to 3.5 inches long
Lifespan: 2 to 5 years
Nature: Peaceful And friendly
Water Temperature: 50 to 77 degrees Fahrenheit
ph level: 6.8-7.5
Required Tank Size: About 10 galloons
Required Water Type: Freshwater is preferable

These are actually not in the actual zebra family but in the minnow family instead. They can be an excellent addition to any community aquarium because they are peaceful and do well in schools of six or more fish.

Their average size is between 2.75 and 3.5 inches long, and they are silver with black stripes running along their body. They can do well in temperatures between 50-77 degrees Fahrenheit. The Zebra Danio is one of the most popular fish for a beginning aquarist because it is very hardy and easy to care for.

They will eat just about any kind of food and can be kept in water that is between 70 and 80 degrees Fahrenheit. It is one of the best cold-water fishes.

Kuhli Loach

Scientific Name: Pangio kuhlii
Size: 3 to 4 inches
Lifespan: Around 10 years
Nature: Peaceful and Friendly
Water Temperature: 64 and 77 degrees Fahrenheit.
ph level: 5.5 to 6.5
Required Tank Size: About 15 galloons
Required Water Type: Fresh and warm water

This type of loach is actually native to Asia but can now be found all over the world, where it has been introduced into different habitats. It is a peaceful fish that does well with other cold-water fishes.

They are slender, so they need plenty of hiding spots in your tank. The Kuhli Loach has dark brown or black markings with yellow, orange, or red patches between the brown markings. They do well at temperatures between 64 and 77 degrees Fahrenheit.

Siamese Flying Fox

Scientific Name: Crossocheilus oblongus
Size: About 4 inches
Lifespan: About 10 years
Nature: Territorial and aggressive
Water Temperature: 70 to 77 degrees Fahrenheit
ph level: 6.5—7.5
Required Tank Size: About 20 galloons
Required Water Type: They prefer moving water mostly.

This fish is actually a type of loach and will grow to be about 4 inches long. They can live in temperatures between 70 and 77 degrees Fahrenheit, and they love to jump out of the water at night, so you need a lid on your tank at all times. They will eat just about anything, but try to give them some sinking pellets or prawns.

Pearl Gourami

Scientific Name: Trichopodus Leerii
Size: 2 to 3 inches
Lifespan: 4 to 5 years
Nature: Peaceful
Water Temperature: 72 to 80 degrees Fahrenheit
ph level: 5.5 to 7.5
Required Tank Size: About 20 Galloons
Required Water Type: Warm and Freshwater

The Pearl Gourami is native to Malaysia and Indonesia but can now be found in waters all over the world that have been introduced. They are peaceful fish that do well in aquariums with other cold-water fishes.

The Pearl Gourami can be identified by their bright colors. They are white, blue, brown, grey, or red with a pink belly. Their average size is 2-3 inches long. The Pearl Gourami needs warm water between 72 and 80 degrees Fahrenheit to do well.

Paradise Fish

Scientific Name:Macropodus opercularis
Size: 1 to 2 inches
Lifespan: 3 to 8 years
Nature: Peaceful, Semi-Aggressive
Water Temperature: 70 to 78 degrees Fahrenheit
ph level: 5.8 to 8.0
Required Tank Size: About 20 galloons
Required Water Type: Freshwater is preferable

Originally native to Africa, where it lived in pools of the Nile River that were very warm, the Paradise Fish can now be found in many different habitats. It is a peaceful fish that does well with other community cold water fishes.

The average size of this fish is between 1 and 2 inches long, and it has beautiful colors such as reds, yellows, oranges, and blues. This type of fish needs at least a 20-gallon tank, and it does best between 70 and 78 degrees Fahrenheit.

Albino Rainbow Shark

Scientific Name: Epalzeorhynchos frenatum
Size: 7 to 9 inches
Lifespan: 5-8 years
Nature: Solitary,Semi-aggressive
Water Temperature: 60 to 70 degrees Fahrenheit
ph level: 6.0 to 8.0
Required Tank Size: About 30 galloons
Required Water Type: Water with sandy substrates

This fish is also called a Freshwater Shark because of its features. It has a black body with a long dorsal fin that curves backwards near the tail, and this dorsal fin must be kept intact by any retailer or private owner.

It is a bottom feeder and does well in colder water, between 60 and 70 degrees Fahrenheit. The average size of this fish is between 7 and 9 inches long, and it eats just about anything that moves.

Betta

Scientific Name: Betta splendens
Size: About 2.5 inches
Lifespan: 3-5 years
Nature: Interactive and Friendly
Water Temperature: 75 to 82 degrees Fahrenheit.
ph level: 6.5 to 8.0
Required Tank Size: About 5 galloons
Required Water Type: Tap Water, Spring Water

This species is actually called the Siamese fighting fish because it will fight with other Bettas. If you are looking to keep your Betta as a pet, then you need at the very least a 5-gallon aquarium. The Betta is beautiful with its colours of blue, green, cream, or red on top of its body with dark blue or black colours underneath. They will eat just about any kind of food and can be kept in water that is between 75 and 82 degrees Fahrenheit.

Golden Dwarf Gourami

Scientific Name: Trichogaster lalius
Size: 2 to 2.5 inches
Lifespan: 4-8 years
Nature: Peaceful and shy
Water Temperature: 64 to 82 degrees Fahrenheit
ph level: 6.0 to 7.5
Required Tank Size: 10 to 30 galloons
Required Water Type: Sluggish water with heavy vegetation

They are also called Sunbeam Fish because of their beautiful colour when they catch the light in certain ways. This species is actually closely related to the Pearl Gourami, but it has red striping that is broken up with yellow.

Their average size is about 2-2.5 inches long, and they can be kept in temperatures between 64 and 82 degrees Fahrenheit.

Weather Loach

Scientific Name: Misgurnus anguillicaudatus
Size: About 6 inches
Lifespan: About 10 years
Nature: Semi-aggressive
Water Temperature: 64 to 70 degrees Fahrenheit
ph level: 6.0 to 8.0
Required Tank Size: 15 to 20 gallons.
Required Water Type: Cold And Freshwater.

These fish are actually native to the Asian mountains where there is cold water that can be very deep. They have a shovel-shaped nose and very small eyes, but these features help them search for food in mud or very soft sand.

The average Weather Loach is about 6 inches long, but it can grow up to 12 inches in length. They need a tank that is at least 20 gallons because of their large size, and their water needs to stay between 64 and 70 degrees Fahrenheit.

Bristlenosed Catfish

Scientific Name: Ancistrus
Size: 6-8 inches
Lifespan: About 12 years.
Nature: Semi-aggressive
Water Temperature: 50 and 76 degrees Fahrenheit
ph level: 6.5—7.5
Required Tank Size: About 40 gallons
Required Water Type: Highly oxygenated water

These fish are actually sensory, so they have very sensitive barbels on their noses that help them search for food in the darkness of muddy waters. They are usually brown or black on top with white underneath, but they also have an X marking that is orange.

The average length of this fish is about 6-8 inches long, and it needs a minimum. They are one of the best cold-water fishes because they have adapted to live in both deep and shallow waters.

The average Bristleosed Catfish is about 6-8 inches long, so you need at least a 40-gallon tank if you want to keep 2 or more of these fish. You can have them in water that is between 50 and 76 degrees Fahrenheit.

Lace Catfish

Scientific Name: Corydoras paleatus
Size: 2.5-3 inches
Lifespan: About 4 years.
Nature: Peaceful and shy, but they can be very active at certain times of the day.
Water Temperature: 68 to 72 degrees Fahrenheit
ph level: 6.0—7.8
Required Tank Size: About 10 gallons.
Required Water Type: Highly oxygenated water with heavy vegetation.

There are 29 known species of Lace Catfish, but the most common one is Corydoras paleatus. This species actually has two different colour forms, and each form can have either a brown or gold body that has small brown spots.

The Lace Catfish comes from Asia, but it can now be found all over the world after being introduced to new habitats by humans. It has poisonous spines that are held under their fur-like skin that cannot injure other fishes.

The Lace Catfish must be kept with other cold-water fishes because it is known to be a suckerfish that eats the slime of other fishes and may suck on other smaller species.

Their average size is about 8 inches long, but they can grow up to 24 inches long. You need at least a 40-gallon tank for this type of fish, and their water should stay between 50 and 70 degrees Fahrenheit.

Corydoras Catfish

Scientific Name: Corydoras
Size: 2-3 inches
Lifespan: About 4 years.
Nature: Peaceful and shy
Water Temperature: 75 to 80 degrees Fahrenheit
ph level: 6.0—7.8
Required Tank Size: About 20 gallons.
Required Water Type: Highly oxygenated water with heavy vegetation.

Corydoras Catfish come from South America, and they are commonly known as cory catfish. They are used in aquariums because they eat algae and other types of food that contribute to poor water quality, which can help control disease in the tank.

Corydoras Catfish love eating sinking pellets and flake food, but they need to be added directly to the tank or into a separate container with water from the tank because they are sensitive to changes in temperature.

Their natural habitats are rivers and streams, so they need a very large aquarium when fully grown because they like to swim around and explore their surroundings. They are peaceful towards other species of fish, but they will eat smaller fish if there is not enough food for them to share.

Corydoras Catfish need a tank that is at least 20 gallons, but it is important to make sure that they always have access to good quality food because the food needs to sink to the bottom of the tank where they can find it.

There are many types of Corydoras Catfish, and each one is unique in its color pattern and behavior. They are sensitive to changes in water temperature, and they should be kept between 75 and 80 degrees Fahrenheit.

It is important to make sure that they always have access to good quality food because the food needs to sink to the bottom of the tank where they can find it.

Synodontis Catfish

Scientific Name: Synodontis Multipunctatus
Size: 4-7 inches
Lifespan: About 10 years.
Nature: Peaceful and active, but they can be very shy when they are frightened or stressed.
Water Temperature: 68 to 76 degrees Fahrenheit.
ph level: 6.0—7.8
Required Tank Size: About 50 gallons.
Water Type: Slightly acidic water with a lot of plants and rocks for them to hide in.

The Synodontis Catfish is also known as the Spotted catfish or Squeaker because it makes squeaking sounds when its body comes into contact with objects in the tank.

The Synodontis Catfish comes from Africa, and it is known by the scientific name of Synodontis multipunctatus. This species is very different from most other fish because it uses its fins to walk across the floor of an aquarium instead of swimming.

It eats insects that fall into the tank at night, so it will spend most of its time on the bottom looking for food. The Synodontis Catfish needs a tank that is at least 50 gallons when fully grown because they are very aggressive towards other fish.

They should be kept between 70 and 80 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

There are many types of Synodontis Catfish, and each one is unique in its color pattern and behaviour. This species likes to eat insects that fall into the tank at night, so it will spend most of its time on the bottom looking for food.

They need a tank that is at least 50 gallons when fully grown because they are very aggressive towards other fish.

Lake Tanganyika Cichlids

Scientific Name: Cyphotilapia
Size: About 8 inches.
Lifespan: 5-7 years.
Nature: Aggressive and very territorial, these fish are best kept in a species tank or with other Lake Tanganyika Cichlids.
Water Temperature: 75 to 80 degrees Fahrenheit
ph level: 7.5—9.0
Required Tank Size: About 50 gallons.
Water Type: Moderately hard and alkaline water with a higher ph level

There are many types of Lake Tanganyika Cichlids, and each one is unique in its color pattern and behavior. The most famous species from this area of Africa is known as the “Electric Yellow Labido” or “Labido” for short, and it has a bright yellow color pattern along with black stripes.

This fish needs to be kept in aquariums that are at least 50 gallons when fully grown because they can grow up to 8 inches. Lake Tanganyika Cichlids are aggressive toward smaller fish, but they will not bother humans as long as they are fed regularly.

It is important to make sure that their aquarium always has very good water quality because these fish can be very sensitive to changes.

There are many types of Lake Tanganyika Cichlids because each one is unique in its color pattern and behaviour. They are aggressive toward fish that are smaller than them, but they will not bother humans as long as they are fed regularly.

They need a tank that is at least 50 gallons when fully grown because they can grow up to 8 inches.

Red Tail Shark

Scientific Name: Epalzeorhynchos Bicolor
Size: About 8 inches.
Lifespan: 5 years old.
Nature: Peaceful and active, but can be aggressive when they are kept in small aquariums.
Water Temperature: 64 to 70 degrees Fahrenheit.
ph level: 6.0—8.5
Required Tank Size: About 50 gallons.
Water Type: Moderately hard and alkaline water with a higher ph level.

The Red Tail Shark is also known as the “Bleeker” because it was named after the famous Dutch ichthyologist who first discovered this species of fish in 1851. It can be found in Thailand, parts of Malaysia, and on the islands of Australia.

This species is very calm when it is kept in an aquarium with the right amount of space because it only grows to about 8 inches in length. They are known for their bright red tail that gives them their name, but they can come in many different colors, including black, white, blue, yellow etc.

They are also called Acanthistius Brasiliensis because they are found living along the waters of Brazil. Their average size is about 5-8 inches long, but there have been reports of Red Tail Sharks reaching up to 9 feet in length.

You need at least a 100 gallon tank for this fish because of its large size, but you have to remember that they will eat just about any kind of food, including sick or injured fish in your aquarium. They are at their happiest when the water temperature is between 64 and 68 degrees Fahrenheit.

Pike Cichlid

Scientific Name: Cichlasoma
Size: About 11 to13 inches.
Lifespan: 15 years old.
Nature: Aggressive and very territorial fish that are best kept alone or with other Pike Cichlids from South America. They will eat just about any fish they can fit in their mouth, so tankmates must be chosen carefully.
Water Temperature: 67 to 77 degrees Fahrenheit.
ph level: 6.5—8.0
Required Tank Size: About 75 gallons.
Water Type: Moderately hard and alkaline water with a higher ph level.

The Pike Cichlid is also called the Midas Cichlid because of its brownish color that has some yellow coloring mixed into its scales. They are voracious eaters that will eat just about anything that moves, so leave fish flakes and pellets out of your Pike’s diet if you want them to remain healthy.

Not only are they very active, but they are also aggressive to other fish that have an open mouth because that is how they hunt for food. The male Pike Cichlid may get up to 17 inches long, while the female often reaches a length of 11-13 inches.

Their water should be kept between 67 and 77 degrees Fahrenheit because of their cold-water habitat, and you should only keep 1 Pike Cichlid in your aquarium.

Silver Hatchetfish

Scientific Name: Gasteropelecus
Size: About 2 inches.
Lifespan: 5 years old.
Nature: Peaceful and very shy fish that are better kept in smaller groups instead of being kept alone.
Water Temperature: 72 to 82 degrees Fahrenheit
ph level: 6.0—8.5
Required Tank Size: About 20 gallons.
Water Type: Acidic and soft water

The Silver Hatchetfish comes from the Amazon River in South America, and it is known by the scientific name of Gasteropelecus sternicla.

They are unique fish because they actually live on the underside of leaves in extremely fast-moving water, so it is important to make sure that their aquarium has plenty of hiding places for them to feel safe.

This fish also needs a tank that is at least 20 gallons when fully grown because it is considered to be an aggressive fish. It will eat worms, insects, and insect larvae that fall into the tank at night, so it will spend most of its time on the bottom looking for food.

The best water temperature for these fish is between 72 and 82 degrees Fahrenheit, and they only need 1/4 of a pound of food for every 1 inch of their body.

Sunset Hyphno

Scientific Name: Hyphessobrycon erythrostigma
Size: 2.5 to 3 inches in length.
Lifespan: 4 years old.
Nature: Calm fish that are very peaceful towards other tank mates, so they are good community fish to have in your aquarium.
Water Temperature: 72 to 80 degrees Fahrenheit
ph level 6.0—8.5
Required Tank Size: About 30 gallons when fully grown.
Water Type: Slightly hard and alkaline water with a ph level of 7.0 or higher

The Sunset Hyphno comes from South America, and it is known by the scientific name of Hyphessobrycon erythrostigma. This fish needs to be kept in aquariums that are at least 30 gallons when fully grown because they will grow up to 8 inches.

They are an omnivore that likes to eat bloodworms, brine shrimp, beef heart, and other meaty foods. Their water should stay between 72 and 80 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

South American Lungfish

Scientific Name: Lepidosiren paradoxa
Size: Up to 4 feet in length.
Lifespan: About 20 years old.
Nature: Very peaceful, but they are known to be territorial towards other lungfish during spawning season.
Water Temperature: 65-75 degrees Fahrenheit
ph level 6.5—8.0
Required Tank Size: About 600 gallons.
Water Type: Acidic and soft water

The South American Lungfish is known by the scientific name of Lepidosiren paradox, and it comes from South America.

The only reason why they are in the cold water category is that they can adapt to colder temperatures when their habitat starts getting too hot. Just like other South American Lungfish, it can reach up to 4 feet in length, with the average being about 2 feet long.

Although they are not really fish because they breathe through lungs instead of gills, the South American Lungfish comes from Brazil, where it lives in slow-moving or still waters.

The average adult size is about 3-4 feet long, and they need a tank that is at least 5 feet long to live comfortably. Their water should stay between 65 and 75 degrees Fahrenheit, but this fish has been known to survive in temperatures as low as 40 degrees Fahrenheit for brief periods of time.

Red-Bellied Piranha

Scientific Name: Pygocentrus nattereri
Size: Up to 12 inches long.
Lifespan: 15 years old.
Nature: Predatory fish that can be aggressive towards other tank mates; they are best kept in single-species homes with large tanks.
Water Temperature: 78-82 degrees Fahrenheit
ph level 6.5—7.0
Required Tank Size: About 55 gallons when fully grown.
Water Type: Slightly hard, acidic water with a ph level of 6.5 or lower

The Red-Bellied Piranha comes from South America. This type of fish is very territorial when kept in groups, so it is best to only keep one per tank. They are carnivores that like to eat other fish and small invertebrates, but they can be trained to eat dead food.

The Red-Bellied Piranha has razor-sharp teeth that will never stop growing throughout its life, so you need to make sure that it can wear its teeth down by chewing on driftwood and rocks. Their water should be between 75 and 80 degrees Fahrenheit, and they only grow to about 12 inches long.

Tiger Barb

Scientific Name: Puntius tetrazona
Size: Up to 2 inches long.
Lifespan: About 5-6 years
Nature: Peaceful, active fish that need a lot of room because they can be used as feeders in large aquariums if their population gets too high.
Water Temperature: 72-78 degrees Fahrenheit
Ph level: 5.0—7.5
Required Tank Size: About 75 gallons when fully grown.
Water Type: Slightly hard and alkaline water with a ph level of 7.0 or higher

The Tiger Barb comes from Asia. This type of fish lives in large schools, so they need a big aquarium to thrive. They are omnivores that eat bloodworms, small insects, and lots of plants. It is important for these types of fish to have driftwood because it provides them with fiber to keep their digestive tract working properly.

These fishes are members of the Cyprinidae family of fish that is native to Asia, but they can now be found all over the world after being introduced to new habitats by humans.

They are omnivores that will eat just about anything they come across, so try to vary their diet with pellets, flake food, frozen bloodworms, and algae wafers.

They have a lifespan of 5-6 years when properly cared for in captivity. Their water should stay between 72 and 78 degrees Fahrenheit, and they can grow up to 7 inches long.

Chinese Algae Eater

Scientific Name: Gyrinocheilus aymonieri
Size: Up to 10 inches long.
Lifespan: About 7 years in captivity
Nature: Semi-aggressive fish that will work well with most community tank setups if they’re added when the tank is young.
Water Temperature: 70-75 degrees Fahrenheit
Ph level: 6.0—7.5
Required Tank Size: About 100 gallons when fully grown.
Water Type: Slightly hard, alkaline water with a ph level of 7.0 or higher

This fish is always on the move as it searches for food, so it will be a good addition to your aquarium if you want some movement and activity inside of it.

They stay near the bottom of your tank, but they do swim all around its surfaces, foraging for food. The Chinese Algae Eater likes to eat various types of algae, fish flakes, bloodworms, brine shrimp, and daphnia.

They are generally peaceful towards other fish that are smaller than them because they are scavengers more than hunters.

Their water should be kept between 70 and 75 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

Green Terror

Scientific Name: Andinoacara rivulatus
Size: Up to 12 inches long.
Lifespan: About 10 years in captivity
Nature: Semi-aggressive fish that do best when kept with other medium-sized, aggressive fish to keep it company.
Water Temperature: 72-82 degrees Fahrenheit
Ph level: 6.5—8.0
Required Tank Size: About 100 gallons when fully grown.
Water Type: Slightly hard and alkaline water

The Green Terror is named after its bright green fins and tail. The Green Terror comes from South America, and it is known by the scientific name of Andinoacara rivulatus.

They can grow up to 18 inches long when fully mature, and they are members of the Cichlidae family because they come from South American waters. The Green Terror is a carnivore that loves to eat bloodworms, brine shrimp, beef heart, and other meaty foods.

They need a tank that is at least 75 gallons when fully grown because they can be very aggressive towards other fish when they reach adulthood.

Their water should stay between 72 and 80 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

Plecostomus

Scientific Name: Hypostomus plecostomus
Size: Up to 16 inches long.
Lifespan: About 10 years in captivity
Nature: Peaceful fish that work well with most community tank setups if they are added when the tank is young.
Water Temperature: 70-80 degrees Fahrenheit
Ph level: 6.0—7.5
Required Tank Size: About 100 gallons when fully grown.
Water Type: Slightly hard, alkaline water with a ph level of 6.0 or higher

The Plecostomus comes from South America, and it is known by the scientific name of Hypostomus punctatus. They are a small algae eater that likes to eat off of the rocks and plants in your tank, but they also love to eat sinking pellets and flake food.

The Plecostomus is a friendly fish that will coexist with many other types of peaceful fish because it does not have any natural enemies. Its water should be kept between 70 and 80 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

Red-Tailed Catfish

Scientific Name: Phractocephalus hemioliopterus
Size: Up to 3 feet long in the wild.
Lifespan: About 7 years in captivity
Nature: Semi-aggressive fish, so it’s important to keep it in larger tanks with other aggressive types of fish for company.
Water Temperature: 72-80 degrees Fahrenheit
Ph level: 6.5—7.0
Required Tank Size: About 100 gallons when full grown, but they can easily live in a tank that is 10 feet long or more if well cared for.
Water Type: Slightly hard and alkaline water

The Red-Tailed Catfish comes from North America, and it is known by the scientific name of Phractocephalus hemioliopterus. They are a carnivore that likes to eat bloodworms, brine shrimp, beef heart, and other meaty foods.

They need a tank that is at least 75 gallons when fully grown because they can be very aggressive towards other fish when they reach adulthood.

Jack Dempsey

Scientific Name: Rocio octofasciata
Size: Up to 2 feet long.
Lifespan: About 5 years in captivity
Nature: Semi-aggressive fish that needs a tank that is at least 55 gallons when fully grown, but they can easily live in a tank that is 10 feet long or more if well cared for.
Water Temperature: 72-80 degrees Fahrenheit
Ph level: 6.5—7.0
Required Tank Size: About 55 gallons when full grown, but they can easily live in a tank that is 10 feet long or more if well cared for.
Water Type: Slightly hard and alkaline water

The Jack Dempsey comes from South America, and it is known by the scientific name of Piaractus brachypomus. Their natural habitats are in rivers and streams, so they need a very large aquarium when fully grown because they like to swim around and explore their surroundings.

The Jack Dempsey is an aggressive fish that will eat smaller fish like guppies and other types of goldfish, but it can get along with other big species of fish if it is the only one of its kind in the tank.

Their water should be kept between 73 and 80 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

CONCLUSION

This article compiles 27 different types of cold-water fish that can be kept in unheated aquariums. Their water should stay between 70 and 75 degrees Fahrenheit, but it is important to make sure that they always have access to good quality food because they are able to starve themselves for weeks while waiting for new sources.

They all come from various locations throughout the world, and they all have different likes and dislikes when it comes to things like tank temperature, diet, habitat, etc. Some of them are predators that will eat other types of fish, but some of them are very friendly towards other species.

The Jack Dempsey is known for being aggressive because it often eats smaller species of fish even though it can make a good tank mate with other large species of fish as long as they are the only ones in the tank.

All of these options for cold water fish will give you great results, but each one is unique and special in its own way.