How Many Neon Tetras In A 30 Gallon Tank?

Neon tetras are one of the most popular aquarium fish because of their breathtaking appearance and because they are suitable for expert fish keepers and beginner fishkeepers alike. Caring for neon tetras is relatively easy, as long as you have a good idea of their needs. And this understanding begins at choosing how many to introduce to your tank. This is an important question for neon tetras because not only is there a maximum number that you should keep in a tank, there is also a minimum number that should be kept together.

A 30-gallon tank can house around 15-20 neon tetras, which is a good number for this type of fish. Neon tetras like to swim in schools. The bare minimum school size would be 5-6 but a school that small would still run the risk of feeling threatened and could get stressed and aggressive with each other. A much more comfortable school size for neon tetras is around 15. Don’t forget that your tank will also need a large number of plants and vegetation for this type of fish.

neon tetra swimming past green moss

Neon tetra characteristics

Neon tetras are small fish that grow to an average of 1.5 inches long. They are freshwater fish, native to South America, and are common in the Amazon. Their stand-out characteristic is their distinctive and vibrant coloring. They have a turquoise blue line from their eyes to their adipose fin and then a red stripe from their middle to their caudal fin. Their fins are essentially transparent. Neon tetras can fade this coloring if they are feeling threatened, or sick, or if they are resting,

Farming of neon tetra has led to the development of varieties that differ from the original red and blue wildtype, including:

  • longfin – longer fins than the standard

  • albino – no color at all and pink eyes

  • golden – lacking the blue color but retaining the red

  • diamond head – the blue stripe has migrated from the side to the head

school of albino neon tetras
Albino Neon Tetras require the same conditions as standard Neon Tetras

Despite the differences in how they look, all types of neon tetra behave the same way and require the same conditions for them to thrive. There isn’t a huge amount of difference between male and female neon tetras, although the females will have more of a curved belly which can make the blue line look slightly bent when compared to the dead straight blue line of the male.

Neon tetras can be a really fun addition to your tank. Not only are their colors eye-catching and beautiful, but they are also a lively and active fish that will keep you entertained. They are peaceful and non-aggressive, so they can be placed in a tank with other small fish, but larger fish can be a danger to them.

(To find out about suitable companions for neon tetras read our fantastic article – Best Tank Mates for Neon Tetras)

How long do neon tetras live?

In the wild, neon tetras will normally live for around 8 years, but their lifespan is more like 5 years when they are in an aquarium environment.

How many neon tetras in a 30 gallon tank?

If you have a 30-gallon tank, then you will be able to fit 15-20 neon tetras in there without making them too cramped. This is a nice size school for neon tetras so they should be nice and lively with this many of them together.

Remember that the absolute minimum number of neon tetras that should be housed together is around 6. And even this size school can lead to your neon tetras becoming aggressive and stressed. Neon tetras feel safer in larger schools and, in the wild, can even be found in schools that run into the thousands.

The other benefit of having a larger school of neon tetras is that the larger the school, the more lively and active they will be. This will make them much more entertaining to watch and can be really quite mesmerizing.

how many neon tetras in a 30 gallon tank

How to set up a neon tetra tank

So you have your tank, and you know how many neon tetras you can fit in it. Let’s take a look at the next steps to getting set up to bring your fish home.

1) Don't add neon tetra to a newly set-up tank

Neon tetras are very, very sensitive to changes in the chemical composition of their tank water. To the extent that they can die quite easily if placed into a tank that has been newly cycled. You should only add neon tetra to a tank that is already established.

This is because during the initial cycling process, while you are waiting for the filter to get built up with beneficial bacteria, the ammonia and nitrite levels can build up to levels that can be fatal to neon tetras. Some fish are able to tolerate some amount of ammonia and nitrite so can be added slightly earlier, but neon tetras are so sensitive that you can only add them once the cycling process is complete.

2) Make sure the water conditions are right

Because neon tetras are so sensitive to the condition of the water, you will need to be careful to make sure that the conditions are just right.

  • The temperature should be 70oF – 80oF

  • The pH should be 6-7

  • The water should be soft (no more than 10 dGH)

  • There should be no nitrite and no ammonia

  • There should be less than 20 ppm of nitrate

When it comes to cleaning your tank, you need to be very careful about the water chemistry changing too much. Aim for a 25% water change every week. Doing such a small percentage at a time shouldn’t change the water conditions too drastically, which will help keep your neon tetras safe. Neon tetras don’t produce much waste, so you can get away with just a regular sponge filter to keep the water clean.

3) Make the tank close to their natural habitat

The last thing you want for neon tetras is a tank that is bare and bright. Your goal is to mimic the dense vegetation that neon tetras would live in naturally. So think about the dark green environment of the Amazon and try to follow that as closely as possible. You will need to make your tank heavily planted, and you could even add some driftwood. Make sure that your neon tetras have lots of dark nooks and crannies to explore. Floating plants are a good idea to make sure that the water is dark and that your neon tetras have plenty of low-light places to explore.

Some good plants for neon tetra include:

  • Ludwigia repens

  • Brazillian pennywort

  • vallisneria

  • cabomba

  • Cryptocoryne wendtii

  • frogbit

  • dwarf water lettuce

  • red river floaters

Brazilian Pennywort
Brazillian Pennywort is a good plant to have in a neon tetra tank

You should also make sure that your substrate is dark and you could even darken 3 out of 4 walls of the tank to really make sure that it doesn’t get too bright or that the tank isn’t too exposed. In terms of lighting, it is a good idea to keep it as subdued as possible. So use a low-wattage fluorescent light and aim for around 2 watts per gallon of your tank.

These tank conditions should keep your neon tetras happy and healthy for many years to come. Neon tetras don’t require a huge amount of care, as long as you set the conditions up in the right way in the first place. The most important thing that needs monitoring is the water chemistry because of how sensitive they are, but this can easily be made into a no-hassle routine.

(We have a guide on caring for neon tetras – read it here!)

Neon tetra diet

One of the characteristics of neon tetras that make them easy to care for is that their diet is relatively simple when compared to some other species of fish. They are omnivores, so they can eat both plants and animals and they are happy to tolerate food given in a variety of forms, including flakes, granules, freeze-dried, pellets, and live food.

There are lots of fish food available that will be a complete diet for your neon tetra. In other words, they can meet their nutritional needs completely just on the flakes/pellets/granules that you can buy from the store. You can always supplement this food with some live or frozen food as a treat. Try to make the live food as small as possible because neon tetras will try to fit food that is far too big into their mouths!

Some good suggestions are:

  • live fruit flies

  • live black worms

  • frozen or freeze-dried blood worms (small)

  • live or frozen daphnia

  • live or frozen brine shrimp

  • frozen tubifex

tray of frozen brine shrimp
Frozen brine shrimp is a great food choice for Neon Tetras

How often should neon tetra be fed?

You should follow the same feeding schedule as you would for other similar aquarium fish. Young neon tetras can be fed twice a day, and then move to once a day for mature fish. An important thing to remember with neon tetra is not to give them too much food as it will just be left to rot and this can cause the chemistry of the water to change so much that it can be deadly to your fish. A good rule of thumb is to feed them enough that they can eat it in 3 minutes. If there is any leftover food after this time, then remove it.

Neon tetra disease

Despite its name, neon tetra disease isn’t only found in neon tetras. Its name stems from the fact that it was first discovered in that species of fish. It is a disease that, for the moment, there is no cure and it is fatal. If you have other fish in your tank and you notice signs of neon tetra disease in your neon tetras, you should always remember that the other fish are not immune.

Neon tetra disease is a parasite-borne disease. It is transmitted through eating the flesh of infected fish or infected live food. Once the parasite has entered the body, it starts a process that is quite slow but it will eventually get severe enough that the fish will die. It’s pretty gruesome but, essentially, the parasite eats the fish from the inside out. Catching the disease as quickly as possible is essential if you want to keep the rest of the fish in your tank safe.

neon tetra against blurred gravel background

Symptoms of neon tetra disease

1) Restlessness

This is very often the first sign that you will notice and, with schooling fish like neon tetra, it is relatively easy to spot. If one of your fish stops schooling with the other fish, then this is a clear sign that something is very wrong.

2) Skin discoloration

This is caused by the parasite affecting muscle tissue and it is often contained in small areas. It usually starts near the spine.

3) Lumps

You may spot lumps on your fish that have been caused by cysts developing.

4) Problems swimming

As the fish starts to lose control of their muscles they will start to have trouble with swimming.

5) A curve in the spine

This is a symptom of the final stages of the disease.

How to treat neon tetra disease

There is no cure for neon tetra disease, so the best course of action is to remove the affected fish as quickly as possible. This is vital if you want to prevent the other fish in your tank from contracting the disease. Fish will feed on dead fish when given the opportunity and if the dead fish had neon tetra disease then it will be passed on.

It is also a good idea to quarantine any new fish for two weeks before you add them to your main tank so that you can be sure they aren’t carrying the disease.

large shoal of neon tetras

Final thoughts

Neon tetras are a wonderful addition to any home aquarium. A 30-gallon tank is a great choice for neon tetras because it allows you to introduce 15-20 fish, which is a really nice size school. In a school this size, your neon tetras will be happy and active. It also gives you enough room to add plenty of the plants and vegetation to make the tank as close to the neon tetras’ natural environment as possible.