If you’re considering getting some cold water fish for your aquarium, you have a lot of options. In fact, there are so many different types to choose from that some aquarists have trouble picking!

That’s where this guide will come in handy.

In it, you’ll find information about all the best fish for cold water tanks. Many don’t even need heaters!

By the time you’re done reading it, you’ll know which species interest you the most.

1. Endler’s Livebearer

The Endler’s Livebearer is a fantastic cold water fish for your aquarium. They’re not only quite colorful and pleasing to look at, but they’re easy to care for as well.

One Endler's Livebearer in a cold water aquarium

You’ll sometimes see this fish referred to as Poecilia wingei since it’s technically part of the common guppy family. Theses fish are quite hardy and can handle a wide range of water and habitat requirements.

When it comes to water temperature, they have an acceptable range of 64°F to 82°F. This is not only very generous, but rather chilly as well.

We recommend these fish to pretty much any aquarist. They’re great for anyone looking for cold water fish but are a strong choice in general.

  • Size: 2 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 20 gallons
  • Water Temperature:

2. Bloodfin Tetra

Bloodfin Tetras are a species we absolutely love. They’re low-maintenance, beautiful, and get along with a large number of other fish.

A group of Bloodfin Tetras swimming in a tank with no heater

Their simply color combination makes them very fun to observe especially since you’ll be keeping them in a group. Like most types of tetras, these fish aren’t very large and can be kept in a pretty small tank.

When it comes to setting up their habitat there’s not much to worry about as well. They can thrive in cold water, a range of pH levels, and a variety of decorations and layouts. Simply drop in some plants and you’ll be just fine!

  • Size: 2 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 64°F to 82°F

3. Odessa Barb

Odessa barbs are often overlooked by freshwater aquarists. For whatever reason, these fish don’t get the attention they deserve.

A male Odessa Barb

We’ve been fans of them for years and love the versatility their hardy nature provides. They can do well in cooler waters and will happily coexist with a variety of different tank mates. They’re compatible with the majority of fish on this list.

As long as you give them some variety in their diet and provide a solid habitat, Odessa Barbs will be quite happy. You can also breed them if that’s something you’re interested in as an owner.

  • Size: 3 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 30 gallons
  • Water Temperature: 70°F to 79°F

4. White Cloud Mountain Minnow

The White Cloud Mountain Minnow is a great freshwater fish that can thrive in colder temperatures. They’re a species that not many people pay attention to, but that’s something we’ve never understood.

A White Cloud Mountain Minnow eating

These fish are often compared to Neon Tetras since they look rather similar. They’re quite affordable, easy to care for, and are compatible with many different kinds of fish.

We often encourage aquarists to give this species a shot since because they’re such a pleasure to own. You can keep them in a variety of different habitats without any issues as well.

  • Size: 2 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 10-15 gallons
  • Water Temperature: 64°F to 72°F

5. Sunset Variatus Platy

This is a type of platy that you don’t hear many people talking about. But if we had to choose, this would probably be our favorite!

Sunset Variatus Platy swimming by itself

The Sunset Platy is a great all-around fish that can do well in a number of different conditions. They’re relatively easy to care for and do well in slightly cooler water.

But wow are they pretty! This is one of the most colorful freshwater species out there. They’re addicting to watch swim around in the tank. There aren’t very many fish with a bright yellow that can compete with the Sunset Variatus Platy.

If you’re looking for a cold water fish that adds a lot of color, we recommend giving these creatures a shot.

  • Size: 2.5 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 15 gallons
  • Water Temperature: 72°F to 82°F

6. Panda Corydoras

This is one of the most popular fish in the aquarium scene. The Panta Cory is a species that can be found in many tanks all over the world, and for good

A Panda Corydoras resting on the substrate

They’re very pretty fish that have a neat color pattern. This makes them a great fish to observe.

Caring for them is rather straightforward as well. As long as you know their fundamental requirements you shouldn’t have any trouble keeping this fish.

They’re peaceful which gives you a lot of options when it comes to tank mates as well. Panda Corydoras are often used in community tanks because of this trait.

  • Size: 2 inches
  • Difficulty: Intermediate
  • Minimum Tank Size: 10 gallons
  • Water Temperature: 68°F to 77°F

7. Fancy Goldfish

Fancy goldfish are a popular type of goldfish that tend to have more of an elaborate aesthetic than some of the standard variations. They share a lot of the same traits as other goldfish, they just look different.

A group of fancy goldfish in a cold water aquarium

These fish are great for cold water aquariums since their natural temperature requirements are quite low (this can be as low as 50°F). A lot of the time they don’t even need heaters!

Fancy goldfish will get along with many other species and don’t require a lot of effort to keep healthy. There are usually some species-specific details you need to be aware of, but nothing extreme.

  • Size: Species-dependant
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: Species dependant
  • Water Temperature: Species dependant 

8. Mosquito Fish

This is a very neat species that is often kept in ponds. However, some aquarists like to keep them in tanks as well.

No matter what your preference is, we thought it would be foolish not to include them on our list.

These fish get their name from their aggressive consumption of insect larvae. This is why so many people like them for ponds. These fish will keep things bug-free!

Mosquito fish are extremely easy to care for and are quite hardy. They’ll handle almost all living conditions with ease. They will show some situational aggressiveness from time to time, but that’s not very common behavior.

  • Size: 3 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 65°F to 75°F

9. Bristlenose Pleco

This is one of the most popular species in the freshwater aquarium community as a whole, and they make great cold water fish.

A Bristlenose Pleco suctioned on to the side of an aquarium

The Bristlenose Pleco has a very interesting look that can’t be ignored. On their head and nose area, they have a series of appendages that protrude in various directions. This is why they’re also called the Bushy Nose Pleco.

One of the reasons these fish are so popular is their versatility. You can put them in almost any tank, with almost any other species. They really don’t care!

Out of all the fish we recommend to our readers, this could be the species we suggest the most.

  • Size: 3 to 5 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 25 gallons
  • Water Temperature: 60°F to 80°F

10. Rosy Red Minnow

Rosy Red Minnows are one of our favorite species, and near the top of the list when it comes to cold water fish for your aquarium.

Two cold water Rosy Red Minnows

These fish are very hardy and can thrive in a variety of different conditions. They can even be used as feeder fish if you so choose.

They can survive in water temperatures as low as 50°F which means you can keep them in tanks without a heater (if it works with the rest of your setup). They don’t need anything in particular when it comes to their habitat as well, so you can plan around their tank mates.

  • Size: 2 to 3 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 10 gallons
  • Water Temperature: 50°F to 78°F

11. Asian Stone Catfish

These little critters are one of our favorite freshwater catfish species to keep in cold tanks. They’re hardy, peaceful, and very easy to care for.

And boy are they small!

Part of what makes the Asian Stone Catfish so adorable is their tiny size. This makes them a great nano fish for small tanks as well.

These fish have an extremely interesting look that makes them stand out (or blend in) compared to many other species. It can be hard to spot them at times! Their bodies are very textured and they almost look like they’ve been rendered by a bunch of polygons.

  • Size: 1.25 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 5-10 gallons
  • Water Temperature: 64°F to 75°F

12. Celestial Pearl Danio

The Celestial Pearl Danio is a gorgeous species that many aquarists love. Their interesting pattern and colors make them a great choice for anyone looking to bring some color to their tank.

Two Celestial Pearl Danios exploring their tank

This species is also a good choice if you favor low-maintenance fish. While there are some elements of their care you’ll need to familiarize yourself with, they’re not very difficult to keep.

These fish are best for well-planted aquariums. Not only is this what they’re used to in the wild, but the green vegetation really makes their colors pop!

We recommend this species to other aquarists all the time. Unless you’re looking for a very cold tank, there’s no reason not to give them a shot.

  • Size: 1 inch
  • Difficulty: Intermediate
  • Minimum Tank Size: 10 gallons
  • Water Temperature: 73°F to 79°F

13. One-Sided Livebearer

This species is not found in very many tanks. In fact, there’s still some debate about their ideal water parameters!

A yellow One-Sided Livebearer

But what’s clear is that these are great cold water aquarium fish.

The One-Sided Livebearer is a simple, yet elegant fish that can thrive in low temperatures. This species is hardy, easy to care for, and peaceful. However, it’s usually best to keep them in a species-only tank.

They got their name from the fact that they always mate on one side. This behavior is quite interesting to watch, so if you’re a breeder you might be in for a treat!

  • Size: 4 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 10-15 gallons
  • Water Temperature: 64°F to 73°F

14. Pygmy Sunfish

The Pygmy Sunfish is a very pretty species that’s one of the best fish for cold water aquariums. The funny thing is not many people know about this fish (even the ones that want to keep fish without a heater).

A male Pygmy Sunfish in a tank with no heater

Out of all the fish on this list, the Pygmy Sunfish is up there in terms of its ability to handle low water temperatures. With a minimum of 45°F, it’s hard to find another species that matches.

They’re not very hard to care for and are rather active fish. This makes them great for aquarists looking for a cold water option that doesn’t sit around at the bottom of the tank all day!

We highly recommend taking some time to do a little extra research into this species before you decide to buy. While they’re not overly difficult, there are a few areas of care that you’ll need to be familiar with.

  • Size: 1.25 inches
  • Difficulty: Intermediate
  • Minimum Tank Size: 5-10 gallons
  • Water Temperature: 45°F to 80°F

15. Dojo Loach

We’ve been massive fans of the dojo loach for quite some time. This is quite a popular fish because of its unique look and ease of care.

A Dojo Loach in a cold tank

In our opinion, this is one of the most enjoyable fish to watch. They’re quite active and friendly, so they’re always up to something.

With an ability to thrive in water temperatures as low as 50°F, the Dojo Loach should be at the top of your list for fish that don’t need heaters. They’ll be just fine!

It’s worth noting that you’ll need a slight larger tank in order to keep them (a good portion of the fish we’ve covered so far are fine with small aquariums). As long as that’s not a problem, give them a shot!

  • Size: 6 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 55 gallons
  • Water Temperature: 50°F to 82°F

16. Paradise Fish

This is one of the most aesthetically-pleasing species on the list. Paradise Fish have mesmerized aquarists for years with their bright colors and flowing tails (us included).

Caring for these fish is something that anyone can do. As long as you take the time to understand their main care requirements and how to set up their habitat, you should be just fine.

With that being said, they can show a little bit of aggression when put in the wrong situation (or with the wrong tank mates). This is easy to work around though. Simply keep them with peaceful fish that are too big to be picked on!

  • Size: 2.5 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 68°F to 82°F

17. Rosy Barb

If you’re a fan of the color red, you’ll love this fish. This species is quite vibrant and will add a whole new visual dynamic to any aquarium they’re kept in.

Two Rosy Red Barbs swimming together

The Roxy Barb is a species that has a dedicated following of aquarists for a number of additional reasons (aside from their coloration). These fish are fairly low maintenance, active, and peaceful.

This gives you a lot of flexibility when it comes to the kind of habitat you want to keep them in. When you combine this with their ability to handle cooler water they get even more appealing.

  • Size: 6 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 30 gallons
  • Water Temperature: 64°F to 72°F

18. Empire Gudgeon

The Empire Gudgeon has some of the most interesting fins out there. There are very few fish like it!

They also have some neat colors too. But for some reason, this species doesn’t get the attention it deserves from the fishkeeping community.

In fact, most of the aquarists who know about them are ones who like keeping cold tanks. As you can see, they can thrive in a wide range of water temperatures.

This is a fairly low-maintenance fish as well. You will have to navigate some aggression from time to time, but if you set then up with a great habitat from the start that won’t be a problem you have to deal with.

  • Size: 4.5 inches
  • Difficulty: Intermediate
  • Minimum Tank Size: 45 gallons
  • Water Temperature: 59°F to 78°F

19. Least Killifish

We’re huge fans of the Least Killifish, especially if you plan on keeping the water temperature a bit on the low side. This small fish is very easy to care for and is a great option for anyone looking for a species that won’t take up a lot of their time.

One Least Killifish in a well-planted cold aquarium

We’ve always said that this species looks a bit like a skinny Pea Puffer. They share a lot of the same colors and have a thin but chunky looking caudal peduncle.

Most of the aquarists we know keep a ton of these fish in their tank. Because of their small size and peaceful nature, you can keep them in large groups and with a wide variety of other species.

  • Size: 1.5 inches for females, 0.75 inches for males
  • Difficulty: Beginner
  • Minimum Tank Size: 5 gallons
  • Water Temperature: 66°F to 75°F

20. Gold Barb

The Gold Barb is a really popular choice for cold water aquariums due to its hardy nature and beautiful bright colors. This fish can brighten up even the dimmest tank with its vibrant yellow.

Gold Barb swimming past a rock

They’re a very mellow and easygoing fish that is compatible with plenty of other species as well. It’s recommended to keep this fish in a school, so that’s why they can’t get away with super small tanks.

If you’re interested in this fish you might have to do a bit of searching before you find it in stock. Due to high demand, Gold Barbs can be a little tricky to get your hands on!

  • Size: 3 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 64°F to 75°F

21. Medaka Ricefish

To be honest, most of the aquarists we talk to don’t even know this species exists. This species goes by two names, the Medaka Ricefish and the Japanese Ricefish.

One adult Medaka Ricefish

Some argue that this fish should technically be considered part of the killifish family or not. However, there hasn’t been a chance in classification yet.

This species is a great choice if you’re looking for a fish that will get along with anyone. If you watch the Medaka Ricefish swimming with other species, they’ll barely even notice them!

This fish is also easy to feed, care for, and even breed. If you’re looking for an under the radar pick to add to your cold water tank, this is definitely a species to consider.

  • Size: 1.5 inches
  • Difficulty: Intermediate
  • Minimum Tank Size: 15-20 gallons
  • Water Temperature: 64°F to 75°F

22. Rainbow Goodeid

This is a very pretty fish that’s hard to get your hands on. Due to their critically endangered status can be a bit pricey and not in stock at most fish stores.

Rainbow Goodeid in a community cold water aquarium

However, if you can find one they’re quite easy to keep. The Rainbow Goodeid is hardy, low-maintenance, easy to feed, and tolerant of a wide range of temperatures and parameters.

Due to the fact that the population of this species is in crisis, it’s important to be absolutely sure before you get one. Do some thorough research into their recommended habitat conditions first.

Spending some extra time to be confident you’re ready and willing to keep them in your aquarium is the responsible thing to do.

  • Size: 2 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20-30 gallons
  • Water Temperature: 67°F to 76°F

23. Axolotl

The Axolotl is an interesting creature that has rapidly grown in popularity over the last few years. While we’re including them on our list of the best cold water aquarium fish, they’re technically salamanders.

A close up of an Axolotl

Another common name for them is the Mexican Walking Fish because of the way they move around the water. While they definitely swim, you’ll also see them using their arms and legs to walk around the tank as well.

For such a unique animal, the Axolotl is actually quite straightforward to keep. They do great in tanks without a heater and don’t have a lot of funky care requirements. They’re very beginner-friendly!

  • Size: 8-18 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 57°F to 68°F

24. Rainbow Shiner

This is a species that’s mesmerizing to look at. True to their name, the Rainbow Shiner is a mix of color and metallic glimmer.

A group of these moving around an aquarium is something you need to see in person. They look like beautiful little shiny darts flicking around the water.

These fish are very active and are almost always in motion. This really makes their beauty worth it!

While these fish aren’t very popular, there’s a committed group of aquarists who’ve figured out what a great species Rainbow Shiners are to own. Consider becoming one yourself!

  • Size: 3 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 55°F to 75°F

25. Hillstream Loach

This species is one of the more unique creatures on the list. With their cool flat built, this fish will stand out among almost any other species.

An aquarium with no heater and one Hillstream Loach

The reason Hillstream Loaches have a low and flat body comes from their natural habitat. These creatures spend their time in waters with very fast currents. This build allows the fish to park themselves on a surface without working hard just to avoid getting swept away.

Because of this, it’s important for this species to have an adequate current. Not only does this help replicate their natural habitat, but it also brings extra oxygen into the water (something this fish needs a lot of).

  • Size: 2-3 inches
  • Difficulty: Intermediate-Expert
  • Minimum Tank Size: 50 gallons
  • Water Temperature: 68°F to 75°F

26. Clown Killifish

The Clown Killifish is a gorgeous species that has gotten a lot of attention in recent years. These tine creatures are very easy to care for and don’t need a complicated tank setup in order to thrive.

A Clown Killifish swimming near the surface of the water

With a minimum water temperature tolerance of 68°F, you can keep these in colder tanks without any issues. They’re very peaceful as well which allows you to match them with a variety of other species.

These fish are interesting because they will spend a lot of time in schools when they’re younger. However, when they grow up you’ll see them start to spend more and more time on their own.

  • Size: 1.5 inches
  • Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 5 gallons
  • Water Temperature: 68°F to 79°F

27. Zebra Danio

The Zebra Danio has a loyal following in the freshwater aquarium community. This is partly because they’re so pretty and partly due to their ease of care.

A Zebra Danio in a medium-sized aquarium

These are one of the most beginner-friendly fish out there. You can keep them in small and cold aquariums, and you don’t have to worry about their diet or interactions with other fish.

It’s a bunch of fun to watch these fish swim around in a group. Their colorful stripes mean they put on an impressive show whenever they move around the tank.

  • Size: 2 inches
  • Difficulty: Beginner
  • Minimum Tank Size: 10 gallons
  • Water Temperature: 64°F to 74°F

Closing Thoughts

As you can see, there are a number of fish that can thrive in cold water aquariums. Some of them are quite popular, and others are under the radar.

The notion of keeping a fish that doesn’t need a heater might feel weird at first. After all, most of the common freshwater fish need one!

But once you get over the strange feeling it’s quite a luxury! It will save you a few bucks and allow you to experiment with keeping a more natural tank.

If there are any types of cold water fish you think we should include in this list just let us know! We’re committed to making our guides as helpful as possible, and welcome the help.

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