Glowlight Tetra 101: Care, Diet, Tank Size, Tank Mates & More

When it comes to the perfect species of shoaling fish for your aquarium, it doesn’t get much better than the tetra. There are so many different species of tetra to choose from, and on the whole, they are easy to take care of.

They are placid, friendly, and being a community fish, they do not tend to cause any trouble.

The glowlight tetras in particular are a fantastic option as the first shoal to place in your tank, and they are a great option for beginners to consider too. They are a freshwater fish that requires tropical tank temperatures.

While they may not be the biggest species of freshwater fish, they are beautiful to look at, especially when the light hits their scales correctly. In this article, we will be talking you through everything you need to know about this beautiful species.

Species Summary

The scientific name for the glowlight tetra is Hemigrammus erythrozonus, and this species of freshwater fish has been prevalent in the fish pet trade since 1933. At first glance, these tetras look fairly plain, however, when the light catches them correctly, they shine beautifully. 

They are a fairly quick fish that prefer to be in a shoal of the same species. They do not do so well when they are placed in a tank on their own, especially as they are quite a small fish. 

The glowlight tetra is native to Guyana in South America, and can be found in their streams and blackwater rivers. On the whole, glowlight tetras are easy to look after, and they cope well when the water levels change slightly. They are a hardy species. 

Care Guide

While these are an easy breed of fish to care for, there are still a handful of things you will need to take into consideration before purchasing them for your tank.

Here is everything you need to know about glowlight tetras:

Tank Size

Even though glowlight tetras are fairly small fish, they can be kept in a fairly small tank. However, even though they can be kept in a smaller tank, you will want to provide them with as much space as possible. The more room they have to swim around the better.

That being said, you can keep a small shoal of around six glowlight tetras in a tank that is around 10 gallons. However, they would then need to be the only fish kept in this tank. 

As they are a shoaling fish, you will need to own more than one of these, as a result you will need to factor this in when thinking about the tank size. Ideally, they should be kept in a tank that is at least 30 gallons in size. This will allow you to add more glowlight tetras to the shoal too. 

Tank Mates

As glowlight tetras are a friendly fish, they can be kept with many fish with no issues. They are great to keep with other tetras, and tank mates such as platy, catfish, snails, shrimp, guppies, mollies, and danio. 

However, as they are a smaller fish, you do not want to put them in a tank with anything too big. This puts them at risk of being eaten. Fish such as cichlids and angelfish should be avoided. Anything that is a fin nipper should be avoided too.

As long as the other fish they are going to be housed with are a small community fish, you should have no issues with keeping the glowlight tetras with them. The other fish will be the problem, rather than these tetras, as they will keep to themselves and will not harm other fish in a tank. 

Same Species Tanks

As glowlight tetras are a community fish, they can be kept in a same species tank with no issues. They thrive from shoals, and can be mixed with other types of community tetras too. However, you will need to ensure that you are not keeping just one glowlight tetra on its own. 

Water Parameters

While you can use a tank light, you should allow the glowlight tetras to have time during the day where this is turned off. This will mimic the environment they are from. The water should be soft, but it can vary slightly due to their hardy nature. 

The temperature should be around 77 degrees Fahrenheit, and the pH levels should be slightly acidic. The levels can be between 5.5 and 7.5. The hardness should be around 15 dGH. 

What To Put In Their Tank

You will want to use either sand or small gravel on the bottom of the tank, along with fresh plants and ornaments for the fish to swim around. They also need a heater and a filter to keep them healthy. 

Common Diseases

Glowlight tetras can experience typical fish diseases such as fungus and fin rot, though they are hardy on the whole. Ich, white spots and parasites are also illnesses that can affect them. Care should be taken to ensure that they are kept in good water conditions, and are treated for any illnesses. 

Food & Diet

A glowlight tetras main diet is flakes or pellets. As they only have small mouths, they cannot eat food that is too large. They can be fed bloodworms or brine shrimp occasionally too. 

They follow an omnivore diet, and because they will not eat food from the floor of the tank, slow sinking pellets are a great option to consider feeding them. They should be fed 1-2 times a day in very small amounts. 


The lifespan of a glowlight tetra is reasonable, while they are not a species that lives for an awfully long time, when looked after correctly, they will live for a good number of years. Typically, this will be up to four years, and while some will live for longer than this, it is unlikely.

When you compare their lifespan to the lifespan of other tetras and freshwater fish, this is a fairly short amount of time. This is why it is so important to ensure they have the correct aquarium environment to ensure that they live for a good number of years. 

You will want to ensure that you are purchasing your fish from a reputable breeder to help ensure that they are not suffering from any diseases, and have good overall health. 


The appearance of the glowlight tetra is quite striking. While they do look fairly plain at first glance, when the light catches them, you are able to see them in all of their glory. They have an orange stripe that runs across their body, and this seemingly glows under the correct lighting. Their body is almost see-through, apart from this stripe and the splash of orange color on their dorsal fin. Their irises are brightly colored. 

When looking at the differences between male and female glowlight tetras, this is minimal. The main differences are that the females are larger than the males. 


Female glowlight tetras are slightly larger than the males. However, the difference is minimal, and you will only really be able to tell the difference when the fish are fully grown. 

On average, a glowlight tetra will be around 1.5 inches (ca. 4 cm) in size. They are a smaller tetra species, though they will grow to be slightly larger than the neon tetra. As they are a smaller fish, they are suitable for slightly smaller tanks. 

Behavior & Temperament

Glowlight tetras are a community fish, and are not aggressive in any way. They are friendly and will keep to their shoal in a tank. They are not intimidating to other fish, and are not known to fin nip others. 

It is worth noting that because they prefer shoals, they do not deal well when alone, and can become quite nervous. They move together as a group, and are a fantastic addition to a community tank.


Glowlight tetras need the correct conditions to be able to breed correctly, and as a result they are a more difficult fish to breed. Rather than being live bearers, they lay eggs. 

When these fish breed, they produce around 150 eggs, and these will need to be taken out of the tank straight away to ensure they are safe. They are also sensitive to light, which needs to be taken into consideration. 

The water needs to have a low pH and be very soft in order to create the perfect breeding conditions for the glowlight tetras. 

Gender Differences: Male vs. Female

The female glowlight tetras are slightly larger than the males. However, the difference is minimal, and you can only really notice the differences when they are fully grown. In addition to this, the female’s stomach is slightly more rounded in comparison to the males.

Fun Facts

  • Glowlight tetras tend to stay in the middle section of the tank, and can rarely be found at the bottom of the tank.
  • They are omnivores