Neon Tetra Temperature Guide (Do They Need A Heater?)

Betta ebook-ban

Last Updated on 2023-10-18

Do you own a Neon Tetra or planning to take care of them? As you may know, maintaining the right temperature is absolutely important for the well-being of these beautiful fish.

So, in this article, I’ll help you discover your Neon Tetras’ ideal temperature range, the importance of a heater in their tank, and how to ensure their comfort in this guide. Keep reading!

Key Takeaways:

  • Neon Tetras require a specific temperature range to thrive, with the ideal range being between 72-78°F (22.2 – 24.4°C) and 75–78 °F (23.9 – 24.4°C) for breeding.
  • Keeping the fish tank warm can be achieved using a heater, covering the tank, increasing room temperature, and adding insulation to the tank.
  • When selecting a heater for your Neon Tetras, consider factors like wattage, tank size, and whether it’s pre-set or adjustable.
  • Outside temperatures can influence the aquarium temperature, so monitoring and regulating it is vital.
  • To ensure the correct temperature, invest in a quality thermometer for your fish tank, and various types are available, such as stick-on, floating, and digital thermometers.

What Temperature Do Neon Tetra Need To Survive?

Given their origin in South America, it is not surprising in the least that Neon Tetras require warmer water to thrive.

The ideal temperature for neon tetras is between 72-78°F (22.2 – 24.4°C). For breeding, the should be between 75–78 °F (23.9 – 24.4°C).

They also require this temperature to be maintained consistently. It is very well possible that the aquarium temperature can rise and fall with the temperature outside of the tank as well.  And, while temperature change is indeed natural, it is when the temperature changes are quick and drastic that it starts to harm the Neon Tetra.

Here’s a video discussing what temperature Neon Tetras need for them to thrive.

Do Neon Tetras Need A Heater?

When you’re keeping tropical fish, you’re told that they all need heaters. However, you may be wondering if this is still the case with neon tetras.

You should always make sure that you add a heater to your tank when keeping neon tetras. They need a temperature between 72-78°F. Even if the temperature is warm where you live, a heater will ensure the temperature never drops too low.

One of the most important tools and pieces of equipment for Neon Tetra temperature balance is an aquarium heater. They are tropical fish, and therefore need to be kept in heated aquariums. While your aquarium may get to the desired temperature range for most of the day, most is not enough for our neon friends.

How To Choose A Heater For Your Neon Tetras

There are a wide variety of heaters to choose from, and the type does matter. Different heaters have different wattages, and choosing the right heater for your tank is crucial. The different wattages are designed for different sizes of tanks.

When purchasing your heater, ensure you do the research to make sure you are getting the correct wattage for your tank. As a general rule of thumb, you should have between 2 .5 and 5 watts per gallon.

You also have the choice between pre-set and adjustable heaters, and which one you choose is entirely up to you and your specific aquarium. Once you have chosen your heater, ensure that you understand it completely. Some may shut off when removed from the water, which is particularly important to keep in mind when cleaning your tank.

Also, it is important to be aware that outside temperature can still affect the temperature of the aquarium, even with a heater. The heater can be set at a certain temperature; however, if the room temperature rises enough, it can also raise the temperature of the tank with it. The same also applies to cooling at night.

The Neon Tetra has no way of communicating with you if they’re feeling too hot or warm, and it’s up to you as the owner to ensure the tank is at the proper temperature at all times. Also, check on your tetras often, as there are usually signs or symptoms when something is wrong, or at least not quite right.

What Will Happen To Neon Tetras When It’s Too Cold?

So, what exactly will happen if your Neon Tetra gets too cold? Well—it’s definitely not good. Any temperature below 60 degrees Fahrenheit will put our little friend into shock and will almost certainly result in either death or permanent weakness.

And while these are the consequences of cold water, there are also adverse effects if the Neon Tetra temperature is too cool as well. Cool temperatures are classified from anywhere between 60 – 70 degrees Fahrenheit (15.5 – 21.1 degrees Celsius). Exposure to these temperatures will result in your Neon Tetra’s metabolism being slowed and can affect their digestion and even their breathing.

There are also a couple of other illnesses that either come from cool water or are amplified when in cool water, including:

  • Fin Rot – an ailment that can be fatal to your fish. Their fins first start turning colors—and, if left for too long, will begin to fall off entirely.
  • ICH – A parasite that causes havoc and damage to fish’s gills and skin.

    (Wondering whether your fish can survive ich without treatment?).

  • Neon Tetra Disease – Another parasitic disease that affects a large number of tetra fish. While not directly from cool water, Neon Tetra Disease will capitalize on a weakened immune system caused by cool water.  The parasite primarily attacks and weakens the muscles, and becomes increasingly more potent over time.

Obviously, none of these are ideal, and you get the picture of just how and why it is so important to ensure your Neon Tetra’s temperature is just right.

What Will Happen To Neon Tetras If It Gets Too Hot?

We have seen just how cold and cool temperatures affect the Neon Tetra—but what if it’s too hot? They are tropical fish, and although they are a bit more resilient when it comes to warmer temperatures outside of their preferred range, if it gets too hot, the effects can be just as devastating as when exposed to colder temperatures.

Too warm is generally any water temperature that is above 78 degrees Fahrenheit (25.6 degrees Celsius), and you can be sure issues will start cropping up when temperatures get to be around 90 degrees Fahrenheit (32 degrees Celsius).

And what exactly happens at these temperatures? A few things, which are also not very good for our little friends:

  • Oxygen Levels and Suffocation: a well-acclimated tank has plenty of oxygen to go around. And, as you’re probably aware, fish breathe oxygen in the water. However, warm water will increase the Neon Tetra’s temperature and metabolism, causing it to become very hyperactive. This becomes a problem in that the more hyperactive the fish is, the more oxygen they consume. But that’s not all—warmer water actually has less oxygen, so it is a bit of a double threat to the Neon Tetra. A threat that can actually cause the Neon Tetras to suffocate.
  • Stress and Agitation: Neon tetras are sensitive creatures, and sudden changes in temperature can cause them to become stressed and agitated. This can lead to a range of health problems, including a weakened immune system, which makes them more vulnerable to diseases and infections.
  • Physical Illnesses: At high temperatures, the amount of oxygen in the water decreases, which can lead to oxygen deprivation in the fish. This can cause them to become lethargic, lose their appetite, and even die. In extreme cases, the heat can also cause their internal organs to shut down, which can be fatal.
  • The Growth of Harmful Bacteria and Parasites: These microorganisms thrive in warm water, and can quickly take over a tank if conditions are right. This can lead to a range of health problems for the fish, including fin rot, swim bladder disease, and other serious illnesses.
betta care facebook group

How Does Sudden Temperature Change Affect Neon Tetras

How suddenly the Neon Tetra temperature changes is also an important factor in the health of your Neon Tetra. If temperature changes are necessary or inevitable, the single most important thing you can do for your Neon Tetra is ensuring that the change is slow and gradual.

Generally, sudden changes in temperature will result in a weakened immune system. This is caused by a combination of stress as well as changes to their digestion. Although the stress is usually temporary, the damage it can cause is irreversible. A weakened immune system further opens your tetra up to the risk of ICH and other bacterial and parasitic illnesses.

And, when it comes to drastic or sudden temperature change, it is usually dropping in temperature that is the most devastating. When the Neon Tetra’s temperature drops quickly – even if only for a short amount of time – they are highly likely to go into shock.

And, while this is not guaranteed to be fatal for the tetra, it will most likely be debilitating and drastically shorten their life span. Their muscles will become weakened, and they will undergo heavy stress. Similar to most animals, but especially fish, stress is like poison. Even a small amount of it can have adverse effects on their health and ultimately shorten their life span.

The same is true for sudden jumps in heat as well. The discomfort caused by the increased heat is enough to cause stress and may start affecting your Neon Tetra on a physiological level.

So, we know that the right temperature and warmth are necessary for a healthy and thriving Neon Tetra, so let’s take a look at how we can ensure we are maintaining this consistent temperature for our aquariums.

How Can You Make Sure Your Neon Tetras Tank Is Warm Enough?

One of the simplest investments you can make that can be a literal lifesaver for your aquarium and your tetras is to get a quality thermometer for your fish tank. This tool alone can indicate the slightest change in temperature, allowing you to respond in time before any significant harm is done.

There are a few options available to you, and some are indeed better than others, but for a higher cost. Here is a quick summary to help you choose what is right for you and your aquarium:

Stick-on Thermometers (LCD)

Although not the most accurate, they are accurate enough for general use. They are one of the cheaper options and are most commonly used in freshwater aquariums. If you are looking for a reliable, inexpensive, and user-friendly thermometer, LCD thermometers may be the option for you.

Floating Thermometers

These thermometers are intended to be fully immersed in the aquarium in order to get a more direct and accurate reading of the water temperature. While accurate, they are still not as accurate as the digital alternative. They are also relatively inexpensive as well.

Digital Thermometers

Definitely the most expensive of the options, however, the advantages can be worth it. One of the biggest benefits is that most digital thermometers come with an alert of some kind to let you know if the water temperature is rising or dropping. This is definitely a game changer and can make all the difference in the event of something going wrong, such as your heater failing.

Which thermometer you choose is up to you and your particular preference and budget. However, what is most important is that you have at least one of these options to ensure that your tank is maintaining the correct temperature at all times.

How to Keep a Fish Tank Warm

As mentioned above, keeping your neon tetra’s fish tank warm is vital to ensure their best health and to provide the most optimal breeding environment for them. Keeping their fish tank warm might sound a little daunting, but here are 4 easy ways how you can do it.

Use a Heater

Invest in a good quality aquarium heater that can regulate the temperature of the water. Set it to the desired temperature, which is usually between 72-78°(22.2 – 24.4°C) and 75–78 °F (23.9 – 24.4°C) for breeding.

Cover the Tank

Use a cover to trap the heat inside the tank. This will also help to reduce evaporation. You may use glass lids as they are the most durable, effective, and versatile type of covers. You may also try making a DIY plastic cover using polycarbonate sheets; but whatever you use, make sure that you don’t cut off your tank’s oxygen supply.

Increase Room Temperature

Even if you don’t have a heater, you can still keep your fish tank warm by simply increasing the room temperature. Keep the room where the tank is located at a warm temperature. This will help to keep the water temperature stable.

Add Insulation to Your Tank

If the tank is located in a cold room, you can add insulation to the sides and back of the tank. Especially during winter, you can insulate your tank and all filtration by wrapping them in blankets, towels, or cardboard. This will help to retain heat.

How Can You Keep Your Tank Warm Without A Heater In An Emergency?

So, say you chose the digital thermometer with the audible alert function. You are enjoying a calm and casual evening, watching television or reading a book. Then–all of a sudden, you– receive an alert. You go to check and see that your heater has quit working entirely.

You can see from the digital display that the temperature is dropping fast. You don’t have a backup heater, and nothing is open. It is going to be night soon, and as the temperature of the room drops, the water in the tank will plummet even faster.

Don’t panic. Here are some temporary measures you can take to keep your tank warm In the event of an emergency:

  • Cover the Outside of the Tank: Cover both the outside of the tank with a thick blanket. This will assist in preventing heat from escaping.
    Cover the Tank with a Lid: This is another way to slow the loss of heat in the aquarium.
    Heaters: Utilize your household heaters by keeping it near the fish tank. This can help slow the loss of heat as well.

There are many other reasons why you may need to keep your tank warm other than the heater failing. That is why it is best to make sure you are prepared for anything. Having a backup generator and backup heater are some ways that you can be much more proactive in the event of an emergency.


What Is the Best Temperature for Neon Tetra Breeding?

The ideal temperature for breeding Neon Tetra is between 75-78°F (22-28°C). It is important to maintain a stable temperature within this range and avoid sudden fluctuations, as this can stress the fish and negatively impact their ability to breed.

Additionally, maintaining good water quality, including a neutral pH and low levels of ammonia and nitrite, can also help create an optimal breeding environment for Neon Tetras.

Can Neon Tetras Live in Cold Temperatures?

Neon Tetras are tropical fish and are not well-adapted to cold temperatures. They are native to the warm, slow-moving waters of the Amazon Basin in South America, where temperatures range between 72-78°F (22-28°C).

They are not able to tolerate water temperatures below 60°F (15°C) for an extended period of time, and temperatures below 50°F (10°C) can be lethal.

Is It Safe to Put Ice Cubes in Your Neon Tetras Tank in The Summer?

Yes, it is safe to put ice cubes in your neon tetra tank in the summer. However, it is important to keep in mind that the temperature change should be gradual to avoid shocking the fish. Additionally, too much ice in the tank could decrease the water temperature to a level that is too cold for neon tetras.

Is 80 F Too Hot for Neon Tetras?

80°F is a little bit too hot for neon tetras, as they are tropical fish and thrive in warm water temperatures between 72°F and 78°F. However, it is important to keep the temperature stable and avoid fluctuations, so a consistent 80°F is better than constant fluctuations.

Sudden changes in temperature can stress the fish and negatively impact their health.


Neon Tetra temperature makes all the difference in both their health and comfort. If properly kept and supported, Neon Tetras make for some of the best and most beautiful aquarium fish to keep. However, to properly care for them, you will need to ensure you have the right equipment to maintain and monitor the right temperatures. The very basics include a thermometer and a heater to ensure that the water temperature is warm (but not too warm!). The investment will be well worth it, and your tetras will thank you for it!


Ultimate Betta Fish Care Guide
About the author

Hey! I'm Nicolas from Iguane Media !

Blogger and Owner of the betta care fish guide
Thanks for reading this blog

I'm an Animal Lover

2 thoughts on “Neon Tetra Temperature Guide (Do They Need A Heater?)”

  1. Hi it’s currently 31*C here and tank is getting to warm. What is best way to cool a tank? It’s going to be warm for few days.

    • Hey Luke,

      You can actually get fans that sit on the top of your tank and blow over the water to keep it cool. Or a regular desk fan can do the same job. Also try to keep your tank out of direct sunlight

Comments are closed.