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Did you know that you don’t always need an aquarium heater for fishkeeping and there are some wonderful coldwater fish species out there that will thrive in your cold climatic region? Sounds cool right? (pun intended)

Take a look at the cold freshwater aquarium species of fish on this list and pick the one that works best for you.

List of Cold Water Fish Species For Aquariums

Here is list of my personal tried and tested cold water tank species that won’t require you to buy a heater or any insulating equipment and are very easy to care for too.

Celestial Pearl Danio (Danio margaritatus)

Description

The body of the Danio margaritatus is green-blue to dark blue. There are also white spots on the body. These white spots are the “pearls” mentioned above. The belly of these fish is bright red like the fins.

On the fins itself, you can observe a black stripe pattern. The tail fin is an exception to this. The basic color blue of the body overflows as a kind of stripe. However, the ends of the fin are bright red.

This species shows some sexual dimorphism: males are bright blue, and females are dull blue-green. 

Habitat & Care

Originating from fast-moving streams and rivers, the pearl danio is accustomed to strong cooler water currents. Good filtration is important because they require a slightly higher oxygen level than other danios.

Although undemanding about water parameters, they do best in neutral (pH 7.0) soft to slightly hard water.

Diet

Pearl Danios will accept all live, frozen, and flake food types. In nature, their diet consists primarily of insects and zooplankton.

To maintain health, feed good quality tropical flake or granulated food and frozen and live foods such as tubifex, mosquito larvae, brine shrimp, and daphnia.

Goldfish

Species Overview Common Names: Common Goldfish Scientific Name: Carassius auratus Adult Size: 8 inches (20 cm) Life Expectancy: 10 to 15 years.

Description

Adult goldfish are generally known for their bright orange color, but they used to appear mainly as greyish-silver or olive-green fish.

Young goldfish are much darker than adults, appearing olive-green or brown. They lighten over time and start turning orange as they mature.

Goldfish can vary in size depending on their habitat. Goldfish kept in smaller indoor aquariums only tend to grow about 2.5-5 cm (1-2 in) long but can grow up to 15 cm (6 in) when reared in larger aquariums.

Habitat & Care

The wild ancestors of these fish lived in slow-moving waters. They thrived even in areas with low oxygen and muddy water. This is why these fish adjust easily to living in manmade ponds. They also prefer habitats with aquatic vegetation to eat.

 

Diet

Most people feed these fish a commercially produced fish food pellet or flake, but they also thrive on feeder fish occasionally. This is because they display omnivorous behavior and eat just about anything easy to consume. Fish in ponds feed on plants, algae, insects, insect larvae, and small crustaceans.

As a snack, many people also provide bloodworms, peas, brine shrimp, and leafy vegetables. However, it is important not to overfeed these fish, as it can cause digestive blockage.

Gold Barb

Species Overview Common Names: China Barb, Gold Barb Scientific Name: Puntius semifasciolatus Adult Size: 4 inches (10 cm) Life Expectancy: 5 years

Description

Golden barbs are shiny, pretty fish specifically named after their oh-so-bright yellow base color. This yellow base is topped with four to seven arrows and dark stripes.

They also have a steeply sloped back and short barbels on the corners of their mouths. 

Habitat & Care

These fish are popular for their hardy and undemanding nature. However, it must be noted that these fish originated from free-flowing streams and rivers, so you will have to use a powerhead in their aquarium to provide them with a decent current in their habitat.

As for the tank size, I recommend a 20-gallon tank or larger, but do not overload it with plants and provide your fish with adequate swimming space.

It must also be kept in mind that it is best if your water is slightly acidic, as this fish prefers soft water. However, if that is not possible, you have the flexibility of a pH range between 6.0 and 8.0, too.

Diet

The gold barb is an omnivore. In the wild, it eats both meaty foods and vegetables, ranging from insects and small worms to plant matter. It should be fed a diverse diet for tropical omnivores, mixed with plant-based flake foods and algae.

The gold barb also takes bloodworms, frozen foods, brine shrimp, and Tubifex worms. It should be fed 2 to 3 times per day.

Rosy Barb

Species Overview Common Names: Red Barb, Rosy Barb Scientific Name: Puntius Conchonius Adult Size: 6 inches Life Expectancy: 5 years

Description

Rosy barbs have bright red coloration with bold black markings. In particular, they have a black spot right before their caudal peduncle.

Their torpedo-shaped body lends itself to their speed, and they are well known as active fish. They have a forked tail and only one dorsal fin. Like most other cyprinid fish, they lack the adipose fin.

Depending on the conditions of your community tanks, your rosy barb can be slightly bigger or smaller. On average, rosy barbs grow to be around four inches.

Habitat & Care

Rosy Barb will require a tank to store at least 30 gallons of water. The temperature must be kept between 64 and 72 degrees Fahrenheit. 

These fish are known to tolerate high nitrate levels and hence can survive the initial nitrogen cycling, so unless the water conditions aren’t extremely bad, you don’t have to worry about much.

Diet

Rosy barbs are omnivores and will eat whatever food they can find. Wild rosy barbs have been known to eat insect larvae, smaller fish, and plant matter.

You can feed your rosy barbs a varied diet of meaty, live, frozen, and commercial foods. About 80% of their diet should be commercial flakes or pellets to provide nutrition and enhance their coloring. The remaining 20% can be supplemental foods such as brine shrimp, microworms, daphnia, and vegetables.

Bloodfin Tetra

Species Overview Common Names: True Bloodfin, Redfin Tetra Scientific Name: Aphyocharax Anisitsi Adult Size: 2 inches Life Expectancy: Upto 5 years

Description

The Bloodfin Tetras body is elongated. Its base color is silvery white with a blue shine. Their caudal- and analfins are red. Some specimens have red dorsal and pelvic fins, and others have transparent fins.

Males have a bit more intense colors, are a bit slimmer, and show a little hook on their anal-fin. They are schooling fish and feel more comfortable when kept in groups. Keep them with at least 7 or more to keep them healthy.

Habitat & Care

In their native environment, Bloodfin tetra lives in tranquil, calm waters in areas usually filled with dense vegetation,

Hence, the aquarium’s habitat should be richly adorned with abundant vegetation. It is even better if you pair it with a dark-hued substrate and backdrop.

Moreover, the filtration system must be effective and the tank must have posses a secure lid to prevent them from jumping out.

Diet

These species require a versatile diet. You must provide them with a staple diet enriched with dried food, such as flakes, micro pallets, etc. 

You can also occasionally supplement their meals by adding live and frozen foods like bloodworms, larvae, and brine shrimp.

Tankmates

Bloodfin Tetras are known to get along with most small and peaceful fish, but they can also be kept with snails or shrimp.

Other peaceful Tetras, Ghost Shrimp, live-bearing fish, and snails are some of the best tank mates for a school of bloodfin tetras.

Hillstream Loach

Species Overview Common Names: Hillstream loach, lizardfish Scientific Name: Balitoridae Adult Size: 2-2.5 inches  Life Expectancy: 8 to 10 years

Description

This 2.5-inch (6.4 cm) oddball fish looks like a miniature stingray because of its streamlined shape, flat underside, and horizontal fins that can tightly grip onto any smooth surface.

Its unusual body is covered with light-colored spots and dark-brown striping patterns.

Habitat & Care

These odd-looking fish are found in streams and rivers with a fast current and plenty of rocks and other structures for shelter.

Hence, their tan should be spacious enough so that they can move freely, just like in their natural habitat. I suggest that you get a tank that can hold 20 gallons of water and heavily plant it with smooth rocks, fine gravel, driftwood, etc.

Ensure that the tank you set up has good circulation of oxygen-rich water, a pH between 6.5 and 7.8, and temperatures of 68 to 74 degrees Fahrenheit.

Diet

These fish species are omnivorous and should be fed a variety of foods. These can include live or frozen food like bloodworms, tubifex worms, glass worms, daphnia, white mosquito larvae, and brine shrimp.

You can also simultaneously slide in high-quality dry foods like sinking pallets, fish flakes, algae wafers, etc.

Just make sure you feed them once only, as they also feed on the aquarium’s algae growth.

Tankmates

Hillstream loaches are pretty peaceful, in my opinion. They will get along with tankmates similar to their size and those who won’t try to nip on them. 

You can try keeping them with goldfish, livebearers, shrimp, snails, tetras, and danios.

Sunset Variatus Platy

Species Overview Common Names: Sunset platy, Variatus platy, Variegated platy Scientific Name: Xiphophorus Maculatus Adult Size: 2-2.8 inches Life Expectancy: 3-4 years

Description

These fish tend to have a slim physique. It usually has one or more dark streaks on the body, black dosts or spots, black cross bands and a crescent mark in the tail root.

Moreover, their bodies can grow up to 5.5 cm and tend to have yellow dorsal fins on an overall blue and gold body.

Habitat & Care

These fishes are cold water fish (duh that’s why they are on this list). So these species thrive well without heaters, given that the water they are kept in is still, the flooring is silty and the vegetation is abundant.

This is because these species come from heavily vegetated canals and springs and need that same environment to thrive.

You can go for a tank of maximum 20 gallon or larger for these species. And don’t worry about the pH, as I have seen platies do well in ranges between 6.8 till 8.5 pH.

Diet

The Sunset Platies are fuss-free eaters and aren’t really picky in nature (honestly, mine will eat anything that I will put in it’s tank).

But if you want optimal health for this aquarium fish you can go for a diverse diet that can involve: dry foods, tropical fish flakes, granules, fish store pallets, brine shrimp, tubifex and bloodworms.

Additionally, you can include boiled veggies, squash, spirulina, cucumber etc as that will boost the holicic health of this fish in the aquarium.

Tankmates

While you won’t see these fish typically schooling together in tight groups but that doesn’t mean that they will not do well with similar sized non predatory tank mates. 

If anything, I have seen them do well with small tetras, rasboras, cory catfish, snails, bristlenose plecos and rainbowfish.

Paradise Fish

Species Overview Common Names: Fork tailed paradisefish, Paradise gourami Scientific Name: Macropodus opercularis Adult Size: 2-3 inches Life Expectancy: 8-10 years

Description

These fish are banded with stripes of vivid color (blue and red mostly). Their caudal fin is generally orange and the other fins mostly don’t have any design on them.

You may also come across some of them having black/blue spots.

Habitat & Care

One thing about Paradise fish is that they are very adaptable and are easily adjusted to many water conditions, surviving in cool and warm water alike.

This is because in the wild you can find these fish in rice paddies and irrigation ditches where the water temperature and conditions can differ vastly but just make sure your tank has live plants.

Apart from that use a 20 gallon tank at least with pH levels ranging from 6 till 8 and perform 25% water changes every couple of weeks, There is no need for any extra equipment because these fish can even cope with different water conditions and water curents. Just be ethical enough to know that extremes are not reached.

Diet

In an indoor aquarium, feed once or twice a day and feed generously. Algae-based flake foods are essential, in addition to meaty foods. Feed small live foods whenever possible. Supplementation should include white worms, blood worms, and brine shrimp. 

Tankmates

These species are dominant species and won’t do well with smaller fish due to it’s aggressive nature.

If you still want to keep it with some species then keep them with larger fish like goldfish, large gouramis, robust cyprinid species, larger characins and loaches.

A general rule is to avoid slow swimmers and fish with long fins that can get bitten.

Warning: Similar to bettas in disposition, paradise fish are belligerent and predatory. They prefer to live alone but will accept some other species of fish as long as they are a good deal larger and non-aggressive.

Rainbow Shiner

Species Overview Common Names: Rainbow shiner Scientific Name: Notropis chrosomus Adult Size: 1.6 to 2.4 inches Life Expectancy: 2-3 years max.

Description

These species have an elongated, streamlined body which is in an iridescent pink colour with a bright golden band running along the midline. Moreover, you will notice that it’s dorsal and pelvic fins both are marked with striking orange and red blotches.

Habitat & Care

Rainbow shiners can usually thrive in a wide range of water conditions and temperature. You just need to make sure that the aquarium you are keeping them is generous in it’s size and has an effective filtration system.

If you want to go above and beyond in taking care of your fish, you can put rocks, bog wood and sturdy aquatic flora.

Diet

These species readily accept high-quality flake or pellet foods formulated for tropical fish. You can also supplement their diet with occasional offerings of live or frozen foods such as bloodworms, brine shrimp, and daphnia to provide essential nutrients.

Tankmates

These are one hella peaceful species and can be housed with a number of tankmates like: neon tetras, harlequin rasboras, corydoras and catfish.

Japanese Rice Fish

Species Overview Common Names: Japanese rice fish, The Medaka Scientific Name: Oryzias latipes Adult Size: 1.5 inches Life Expectancy: 2-4 years

Description

This torpedo-shaped fish grows up to 1.5 inches (4 cm) and often has a blue or silvery eye. There are hundreds of different colors and varieties that have been line bred over the years, such as gold, pearl galaxy, Yokihi orange, Orochi black, blue, Tancho red cap, Miyuki blue, and platinum white.

Habitat & Care

These fish live in small ponds, shallow rivers, and rice fields. They can survive in a wide range of water temperatures (0–42 °C or 32–108 °F), but they prefer a water temperature of 15–28 °C (59–82 °F).

While they can live in even hotter (and colder) temperatures, we prefer keeping them in unheated fish tanks and outdoor ponds since warmer water can increase their metabolism and shorten their longevity.

You will be needing to set up a 10 gallon tank for them that must be clean at all times and has a sponge filter for slower currents. Moreover, use natural driftwood and plenty of aquarium plants to create a comfortable habitat for them.

Diet

Japanese Rice Fish are omnivores and may consume any form of dry food, including pellets and flakes. You can also feed them blood worms, vegetables, mosquito larvae as a treat. Feeding them a small amount twice a day is recommend.

Just keep in mind that the food must be tiny enough to fit into their little mouths

Tankmates

They get along with all kinds of similar-sized, peaceful tank mates that also enjoy cooler temperatures — like white cloud mountain minnows, hillstream loaches, shiners, amano shrimp, and fancy goldfish.

They can also live with adult cherry shrimps. But I faced a situation where my rice fish ate a baby shrimp so just make sure yours is an adult and of similar size.