Skip to Content

Can Neon Tetras Live In Cold Water?

Although there are over forty species of tetra, there is often one species that springs to mind immediately when anyone thinks of them: Neon tetras are vibrant fish that can add so much to the experience of a keeper.

There are specific requirements for these tropical fish that will ensure their good health and longevity.

When preparing to adopt any new fish, keepers should do some research into the environment in which contending species live in the wild. Neon tetras hail from an area of South America near the equator where the temperatures are consistently high.

Neon tetras should always live in tank water at a tropical temperature to mimic their natural habitat.

Why can’t neon tetras live in cold water?

Could a neon tetra survive in a tank with water temperatures lower than 70°F? It is possible that for a small amount of time, a neon school could exist in a tank with low temperatures.

Temperatures below 70°F do occur in the wild and neon populations survive, but water in the wild is never cold. In instances when tropical locals are hit with cold snaps, wild species like neon tetras can experience large decreases in population.

Providing warm water for your neons is a primary way you can provide them with a safe place to live.

Reason #1 Immediate Effect of Cold Water

Any gradual drop in temperature for a fragile neon tetra is detrimental. If the neon is placed in water lower than 60°F, the first effect on the fish will be stress.

Stress in a fish can lead to immediate and severe heart trouble and a drop in immune system function. A fish can die within hours if exposed to prolonged stress brought on by anything, even cold-water temperatures.

Even a young Neon will be unable to cope with exposure to temperatures lower than 60°F. If rescued from cold water before severe shock, there is a chance a Neon tetra can live.

Still, this fish will most likely forever be weakened by exposure to cold water and will be unable to reach tetra lifespan potential

Reason #2 Cool Temperatures Slow Metabolism

Metabolism And Cool Temperatures In A Fish Tank

While cold water lower than 60°F will almost immediately shock a neon tetra and cause death or permanent weakness, cool water can cause harm as well. If placed in cool water of between 60°F and 70°F, a neon tetra will experience a slowing down of metabolism.

Food digestion will become a struggle, as will breathing. Neon tetras exposed to cool water for a short time will more than likely recover.

Older fish, or fish with preexisting conditions may be unable to bounce back after exposure to even these cool temperatures.

Reason #3 Fin Rot and Cool Water

If a tetra exposed to cool water temperatures does survive and doesn’t succumb to stress, it doesn’t mean that the water temperature is suitable. Another danger that can arise from exposure to cool temperatures is fin rot.  

Interesting READ  Can Betta Fish Eat Tropical Fish Food?

Fin rot can render your fish less mobile and create further stress. Fish stricken by fin rot will have discolored fins.

Their fins may also appear frayed. If not moved to a tank environment with healthy water levels, the fish will begin to lose portions of their fins as pieces disintegrate.

Reason #4 Pre-Existing Conditions

No neons should ever be exposed to cooler temperatures, but if returned to a proper tank set up as soon as possible, a tetra stands a good chance of survival. However, if your fish has an unnoticed, pre-existing condition, this can couple with the stress of low temperatures exposure to further endanger the fish.

A keeper, for instance, may not suspect a neon has a weak heart. If this fish is exposed to cool temperatures, the condition may worsen and the likelihood of survival is slim.

Reason #5 Illnesses That Thrive In Cooler Temperatures

One illness that can affect any fish in a freshwater tropical community tank is ich. Ich, or Ichthyophthirius multifiliis, is a parasite that manifests itself in the form of tiny white dots visible on the skin of the fish. These white spots are young ich that feed on a fish.

Upon entering maturity, the parasite with leave a wound on your fish. Neons can succumb to ich if not treated. And, if they are exposed to cold water, this will weaken their immune system. 

A fish with a weakened immune system will be less able to fight off ich. Additionally, ich will cause further stress, and present even more danger to a neon tetra’s immune system, making survival less likely.

By causing danger to the immune system, cool water can also leave neon tetras more susceptible to Neon Tetra Disease. This disease is caused by a parasite that can be introduced to a community tank through the addition of new fish, or through insects fed to tank residents.

Neon Tetra Disease, despite its name, can affect any tropical fish in a community tank. If a tank exposed to Neon Tetra Disease were to also possess cool water temperatures, each fish in the tank would be suffering from stress as well as low metabolism and a weakened immune system.

Neon Tetra Disease

All the tank residents could succumb to Neon Tetra Disease more rapidly due to low water temperatures.

How can I ensure my neons tetras are never exposed to dangerously low water temperatures?

There is no reason that any neons should ever be placed in cool water. Anyone who adopts a tropical fish, especially a species as fragile as neon tetras, should make two very important purchases along with their tank: a thermometer and a heater.

A thermometer is one of the most important items a fishkeeper can have. All pet stores that carry fish supplies will have at least one type of thermometer for purchase.

A novice fishkeeper can acquire a thermometer for less than ten dollars. A second important purchase is a heater. A heater can go a long way in ensuring that tetra tanks are kept at the proper temperature, even when the tank sits in a cooler area of your home.

Interesting READ  Why Are Betta Fish So Popular? (4 reasons!)

Even the most inexpensive heater, costing under fifteen dollars, can be relied upon to provide neon tetras with appropriately warm water.

Are there additional benefits of keeping neon tetras in 85°F water, mimicking their natural habitat?

Neon tetras are not just physically more fragile than other species in the family, but they are also often thought to be more skittish and susceptible to stress. Stress can seriously tax a fish’s body, aggravating possible underlying issues, and contributing negatively to the overall health of the fish.

By maintaining a tank water temperature similar to that in the wild, captive neons will feel more relaxed. The lower the temperature, the more possibility for exposure to unnecessary strain.

Any fish living with a significant level of stress will be more prone to illness. This is especially true for delicate species like neons.

When changing water, should I worry about the water temperature?

The delicate nature of neons requires that a tank serving as a home for the brilliantly colored fish will need routine water changes. A change of one-fourth of the tank water weekly will help to ensure that levels of ammonia and other ever-present, naturally occurring toxins will remain appropriately low.

Fish keepers should keep the water temperature in mind when making a water change. Introduce water slowly, and make sure that the water is at least as high as room temperature.

Pouring in water that is too cold (or too hot, for that matter) can place additional stress on neon inhabitants. Carefully monitor tank temperatures for at least fifteen to thirty minutes after a water change.

If there is a significant difference between water temperature readings after that time, the heater may need to be adjusted.

How to prevent temperature shock when bringing a new tetra home?

Before purchasing neons, completely set up your tank and give it time to cycle. During this time, monitor the water temperature and make adjustments as needed to achieve the suggested temperature of around 80 to 85°F.

New Tetra Home

After purchasing neons, refrain from immediately introducing them into the tank. Instead, place the transport bag into the tank and let it float at the surface.

Leave the bag like this for no less than fifteen minutes to allow water temperatures to sync. Keep a close eye on the neons while they wait to enter their new home and be on the watch for signs of stress such as slight loss of color and escalating erratic movement.

Once at least fifteen minutes have passed, release the new tank residents into their home.


Once a fish keeper has enjoyed watching a school of Neon tetras streaking through a tank in a rainbow of color the gentile species may become a favorite. Despite their delicate nature, neon tetras have become a popular species to keep.

Their requirements are important, but simple to meet. Maintaining a tank temperature of 80 to 85°F for these tropical fish will go a long way to provide Neons with a safe and healthy home.