Ruby Tetra (Axelrodia Riesei): Ultimate Care Guide

Common NameRuby Tetra
Scientific NameAxelrodia Riesei
Temperature68°F – 79°F
Water Parameters5.0 – 6.5 pH
Size1.6 inches
DietOmnivorous with a preference towards carnivorous foods
Ruby Tetra (Axelrodia Riesei)
Ruby Tetra (Axelrodia Riesei)

Ruby Tetra Facts

  • Ruby Tetras were discovered in 1988 and are a relatively new fish introduced into the aquarium trade.
  • Ruby Tetras come from Columbian waters, where they usually do not stray far. This is why they do not have the same wide water parameter and temperature tolerance as other Tetras.
  • Ruby Tetras are a shoaling species that prefer to be kept in a grouping of at least 6. A group of Ruby Tetras can be seen roaming and playing in their aquarium.

Ruby Tetras have a reddish coloration to their bodies. They have black and reddish tail with transparent colored fins. When first placed into the home aquarium, they will not be as vibrant as they will be once they are settled. Their brightness and coloration depend on how well they are cared for, as a happy fish will display much more vivid hues of red. They look best when kept in a tank with a darker substrate so that they provide a brilliant pop of color to your aquarium.

Ruby Tetras can be found in the upper parts of the Rio Meta in Columbia. They can be found in the smaller streams and tributaries in the same area. Ruby Tetras do not venture far from their natural habitat, which is why they are not found in many other places in the wild. They are not as widespread throughout the area as other species.

Ruby Tetra Care

Ruby Tetras are considered easy fish to care for once they are established. Ruby Tetras only come from one place in Columbia, so they are not as forgiving if their water parameters change. They are used to consistency when it comes to their care. By establishing regular water parameter checks and changes, you can provide your Ruby Tetras with the care they require so they can thrive.

Food and Diet

Ruby Tetras are considered opportunistic feeders and micro predators. Ruby Tetras spend their time hunting for insects and tiny invertebrates in the wild. Even though Ruby Tetras prefer to hunt for their food, they will eat pretty much whatever they can fit into their mouths.

In captivity, you can expect your Ruby Tetras to eat whatever you feed them. They are not picky eaters at all. They should be fed a high-quality, varied diet of high-protein small flakes or pelleted foods. You can even offer them live foods as well as a treat. Bloodworms, microworms, tubifex, artemia, and baby brine shrimp are all great choices that are also small enough for your Ruby Tetras to eat.

Ruby Tetras should be fed 2 to 3 times per day, and only enough to completely consume in 2 to 3 minutes to not mess with their water quality.

Ruby Tetra (Axelrodia Riesei)
Ruby Tetra (Axelrodia Riesei)

Ruby Tetra Size & Lifespan

Ruby Tetra can grow up to 1.6 inches in length at full maturity. They can live up to 3 to 5 years if properly cared for. Owners of Ruby Tetras have reported living slightly longer, but their lifespan and adult size directly depend on how well they are being kept and cared for.

Tank Requirements

Ruby Tetras are a small, shoaling species of fish. They grow up to 1.6 inches at full maturity. Ruby Tetras prefer to be kept together in a grouping of at least 6 fish. By keeping Ruby Tetras in a larger grouping, you will be able to really see their beautiful coloration and unique behavior. They are an active species that can be seen exploring their tank and playing with one another.

Ruby Tetras should be kept together in a grouping of at least 6. However, they will be much happier with more Ruby Tetras for their shoal if you have the room. A small grouping of Ruby Tetras should be kept in a minimum of a 10-gallon tank. They prefer a temperature of 68F to 79F and 5.0 to 6.5 pH. Unlike other species of Tetra, they are not as tolerant of a wide range of water parameters, so make sure to establish regular water parameter checks to ensure their water quality remains correct.

Tank Size

Ruby Tetras are shoaling and active fish. However, they are quite small at full maturity. This means that even though you need to keep at least 6 to 7 Ruby Tetras together, you can still accomplish this in a smaller tank. A small grouping of Ruby Tetras will need at least a 10-gallon tank or more. Remember that Ruby Tetras are an active species, and they will appreciate a tank with more space if you have the room. In a larger grouping with a larger tank, you will see them roaming and playing together and displaying their unique shoaling behaviors. 

How Many Ruby Tetra Can I Put in A 10 Gallon Tank?

You can keep 6 to 7 Ruby Tetras together in a 10-gallon tank, but keep in mind that they are an active species that will do best when given the most room for them to roam and play with more tankmates.

Tank Setup

When setting up a tank for Ruby Tetras, you need to remember their natural habitat for reference. Ruby Tetras prefer dim lighting, and floating plants are a great way to accomplish this effect. Owners of Ruby Tetras suggest a darker substrate to help show off their pop of color. Ruby Tetras are like planted tanks with driftwood and rocks, giving them places to hide, explore, and play.

Ruby Tetra Breeding

Ruby Tetras are fairly easy to breed, and they may even breed without help if kept in the correct setup. However, if you want to ensure the survival of the fry, you will want to set up a dedicated breeding tank for them. Ruby Tetras, like most other species of Tetra, provide no parental care to their offspring and will go after their own eggs and fry.

How to Breed Ruby Tetras

When Ruby Tetras are ready to spawn, the male Ruby Tetra and the female Ruby Tetra will perform a sort of embrace where the female releases her eggs, and the male fertilizes them simultaneously. Once the eggs are released, they will scatter and fall below whatever is there for them to rest on until they are ready to hatch. Once the parent Ruby Tetras are done spawning, you will want to remove the parent fish because they will eat their own eggs and fry. The parent fish provide no parental care to their offspring, and unless you intervene, you will most likely not see many Ruby Tetra fry make it to the free swimming stage.

Once the eggs have been fertilized and dropped safely down to rest, they will hatch within a few days, but they are not yet free swimming. They become free swimming after eating the egg sac they are attached to. Once this has happened, they are free swimming and can eat baby brine shrimp, infusoria, and powdered fish food.

Male or Female Ruby Tetra

Unfortunately, Ruby Tetras do not have any visible differences to help tell the males apart from the females until they reach full maturity. Once they have reached full maturity, you can see the females having a more slightly rounded appearance. This is due to them being full of eggs. The best way to ensure you have a breeding pair is to buy a group of them and let them mature together.

Ruby Tetra Disease

Ruby Tetras are not as hardy as other species of Tetras due to their selective habitat in the wild. They have not adapted to tolerate the same wide range of water parameters and temperatures because of their selectivity in natural habitats. If they are being housed in the correct setup with the correct water parameters and temperature and fed the correct diet, your Ruby Tetras will thrive without issue.

Ruby Tetras can be affected by many of the same ailments as other freshwater fish. Some of the common problems for Ruby Tetras include:


Ich is a parasitic disease that appears on your fish’s skin and gills. Ich can be identified by small, white spots on the fish’s body. Ich is contagious, and if left untreated, it will not only spread all over the body of the affected fish, but it will also spread to all of its tank mates. Ich in your aquarium is most likely introduced into it on affected fish or plants you have purchased elsewhere. To avoid spreading ich to your tank, you should take precautions and quarantine any new plants or fish for at least 2 weeks. In the 2 week quarantine period.

Neon Tetra Disease

Neon Tetra Disease was named after the first species of fish that it was found in. Much like Ich, Neon Tetra Disease shows up on the fish’s body in white spots, but the spots on the fish’s body caused by Neon Tetra disease are much larger. Neon Tetra Disease is not as common as Ich, so most likely, if your fish has white spots, you should think of Ich before Neon Tetra Disease. There is no known cure for this ailment, and infected fish should be quarantined from other fish, so they do not infect others.

The best way to ensure that your fish are healthy is to take precautions when introducing new things into your aquarium. It is much better to prevent issues than to try and fix them once they occur. Most of the conditions that can affect fish are caused by improper water conditions, tank setup, or diet. It is important to establish regular water changes and water parameter checks to ensure that your fish are kept in the appropriate conditions and to catch and fix any issues before they become a problem.

Ruby Tetra Tank Mates

Ruby Tetras are small shoaling fish, and the best tank mates for Ruby Tetras are other Ruby Tetras. Even though they are peaceful fish, they are still small enough that most fish will mistake them for food. This limits the fish you can keep in a community setup with Ruby Tetras. However, Ruby Tetras can be kept with Corys, Apistogrammas, other Tetra species, snails, and shrimp.

There are quite a lot of tank mates that are not compatible with Ruby Tetras for a variety of reasons. Most fish are too aggressive, territorial, or large to be housed safely with Ruby Tetras.

Where Can I Find Ruby Tetra for Sale?

Ruby Tetras are a popular fish for the home aquarium, and you can purchase them from pet stores and online for around $15 per fish. Remember that they should be kept in a grouping of at least 6.

Ruby Tetra VS Ember Tetra

The main difference between Ruby Tetras and Ember Tetras is their coloration. Ember Tetras have a more orangish coloration. Ember Tetras have a solid coloration to their bodies and fins, while Ruby Tetras have a distinctive red and black tails. Ember Tetras are also more rounded than Ruby Tetras. Both the Ruby Tetra and the Ember Tetra have similar requirements for water parameters and diet. They both have peaceful natures as well. Both fish are popular in the aquarium trade for the bright pops of color they add to the home aquarium.

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