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Can Neon Tetras Get Pregnant?

The neon tetra is a very popular tank fish. Its bright, glowing red and blue pigmentation along with its hardy nature and low price make it a favourite for many aquarium hobbyists. Right now, you may be curious as to how the fish reproduce and whether or not they can get pregnant?

Can neon tetras get pregnant? The answer is ‘no’. Neon tetras cannot get pregnant. But rather, they spawn eggs whereby females will scatter them at the bottom of the tank to be fertilized by males. If a female has an enlarged belly, it is likely filled with eggs (or excess food). The other possibility could be neon tetra disease.

Now that you know neon tetras cannot get pregnant, let’s explore this topic in more detail. We will discuss how to tell if a neon tetra is male or female, how long it takes to spawn eggs, if neon tetras can breed in captivity and how to go about breeding them. So, if you’re ready to learn more about the reproductive habits of neon tetra fish, then let’s get started!

How Can You Tell If a Neon Tetra is a Female?

There are two ways to tell the difference between a male and female neon tetra. Males are usually slender with a smooth blue line whereas females are rounder with a bent blue line. Males also tend to be larger than females.

How Can You Tell If a Neon Tetra is Pregnant?

There are four steps to determine whether a neon tetra fish is pregnant. These include the following:

Step One – Determining Gender

The first step to figuring out if a neon tetra is pregnant is to determine the gender of the fish. Males are usually leaner than females and a straight blue line running through them. Females are often rounder than males and have a crooked blue line through them.

Step Two – Checking for Belly Swelling

The second step is to check the girth of the fish to see if the belly is enlarged or swollen. Most egg-laying fish such as neon tetras will have very rounded bellies when carrying eggs. This is usually a pretty good indicator that the fish is ready to spawn.

Step Three – Watching for Courting Behaviour

The third step is to observe the tank and see whether the males are exhibiting courting behaviour. Male tetras will ‘dance’ in an attempt to attract females. This usually consists of swimming about in a square-like pattern, jerking back-and-forth. At times, the males will stop and remain almost motionless before returning to this ‘dancing’ behaviour.

Step Four – Getting Prepared

The fourth step involves preparing for the arrival of little fish once it has been confirmed that a tetra is indeed pregnant. Researching how to care for spawning fish is recommended.

Do Neon Tetras Lay Eggs?

Neon Tetras do indeed lay eggs and this behaviour is known as spawning. When the female is ready to spawn, she will scatter the eggs for the male to fertilize immediately. After the eggs are scattered and fertilized, it is recommended to remove the adult fish from the tank to avoid the possibility of the eggs being eaten!

How Long Does It Take For a Neon Tetra To Lay Eggs?

Pregnant neon tetras will spawn anywhere from 60 to 120 eggs for the males to fertilize. Not every egg will hatch, however. It takes on average 24 hours for the eggs to begin hatching. You can expect to see at least 40 to 50 hatchlings from the 60 or more that have been laid.

Will Neon Tetras Breed in a Tank?

Neon tetras will often breed successfully (in captivity) in a separate tank that has been specifically designed for this purpose. The tank should be at least 38 litres (or 10 gallons) with live plants, preferably. It should also contain specific water and light conditions conducive to breeding. See below for further information.

Are Neon Tetras Easy to Breed?

Neon tetras are fairly easy to breed, as long as the tank conditions are right! To do this, you will need to set-up a proper breeding tank, specially prepare the water and control the lighting conditions. The steps to do this include the following:

Setting-Up the Tank

Prepare a separate breeding tank similar to the one the neon tetras already dwell in. A 38-litre or 10-gallon tank with soft (low mineral content) water is recommended. It should also be kept at the appropriate temperature (25 degrees Celsius or 77 degrees Fahrenheit) and acidity (PH of 5 to 6) for breeding. You can add live plants as well for the shelter and security of the fish.

Preparing the Water

Getting water to a temperature and acidity closest to their natural environment will help neon tetras to spawn in captivity. Place a tank thermometer in the water to be sure it remains at 25 degrees Celsius (77 degrees Fahrenheit). Test the PH daily ensure it stays at 5 to 6 using test strips available online or at your local pet shop. Mix one part water with three parts reverse osmosis water to make it soft and reduce mineral content.

Adding a Filtration System

Investing in a corner filter for the tank will help remove waste and bacteria from the aquarium which is necessary for a healthy breeding environment. A good filtration system will improve the changes of successful spawning in a tank.

Adjusting the Lighting Conditions

It is important to keep the spawning tank in a dark or low-light area so avoid placing the aquarium in a bright or sunny room. Neon tetras prefer a darker environment and will thrive in small amounts of light. They do not need total darkness but consider covering the backs and sides of the breeding tank to block out any excessive light.

Adding the Fish

Evening is usually the best time to add neon tetras to a breeding tank so do so after the sun has set. Place both male and female fish (6 to 8 in total) into the tank and allow them to remain there for at least 2 days. Spawning should begin on the first or second day.

Removing the Fish

Eggs are often hard to see in the tank as they are small and translucent. If you look closely, you should see little round balls in the substrate or in the plants. One the eggs have been laid and fertilized, remove the adults from the tank.

Waiting to Hatch

It usually take around 24 hours for baby tetras to hatch. They will look like small splinters of glass swimming about in the tank! Keep the hatchlings or ‘fry’ in the tank in a dark room for about 5 days after. Babies are light-sensitive and will thrive in a darker environment. You can check them with a flashlight from time-to-time during feedings but only for a short while.

Feeding Time

Baby tetras do not eat the same food as adult tetras. You need to give them special food that you can buy online or in your local pet shop. It should be labelled ‘fry’ food. After a few days, you can feed the little ones some brine shrimp as well.

Introducing Babies to an Adult Tank

Baby tetras can be placed in the same aquarium as adults after 3 months or so. Do not put them into a community tank any sooner as they run the risk of being eaten! Baby fish are more prone to disease and very sensitive to injury so be prepared that all may not survive after being introduced to an adult tank.

Rehoming Extra Fish

Chances are you will have anywhere from 40 to 50 hatchlings bred in any one attempt so you may need to find new homes for some of them. Ask your friends or family if they would like to start a neon tetra tank or you could try selling them online as well. Pet shops usually charge around $5 per fish in North America so you will have to adjust your prices accordingly depending on where you live.


In conclusion, neon tetras do not get pregnant but rather spawn eggs that are scattered at the bottom of the tank by the females and then fertilized by the males. If a female fish has an enlarged belly, it is likely filled with eggs. Or, it could be a side-effect of too much food or neon tetra disease. Breeding tetras is fairly easy as long as you follow the necessary. Good luck and happy fish-keeping!

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