Ruby Tetra Care (Axelrodia riesei): Tank Requirements, Diet, Tank Mates & Breeding



Ruby tetras most prominent feature is their bright orange coloration. Their caudal fin has a dark black. The have minimal finnage that is generally colorless. The ventral parts will generally be less colorful then the upper parts of their body.

Ruby tetras are a sexually dimorphic species, which means males and females will have different characteristics. In the case of Ruby tetras, males tend to be smaller than females. Females tend to be rounder and deeper bodied than their male counterparts. Males tend to show stronger coloration than females, especially during mating.

Ruby tetras are typically between 3.75 centimeters to 4 centimeters in size, or 1.5 to 1.6 inches.

Habitat & Tank Condition


Ruby tetras will thrive in slightly acid waters, whose pH is between 6 and 7. There are a variety of products that you can use to reduce pH (increase acidity levels). Botanicals such as Indian almond leaves, blackwater extracts, peat moss, driftwood and pH buffers are viable choices.


Rubies should be kept in an aquarium whose temperature is within the range of 22 to 26 degrees Celsius, or 72 to 80 degrees Fahrenheit. Most people will need a heater to maintain temperatures within this range.

We recommend Fluval-E and the EHEIM Jager.

Tank Size

Even though Ruby tetras are quite small, a 10 gallon or bigger aquarium is required. This is because tetras are a schooling fish and must be housed with a group of at least 6. If you plan on adding more fish, add 2 gallons for each additional fish.


A filter will help maintain the quality of the water and ensure that you fish remain healthy and comfortable in their aquarium.



Ruby tetras are omnivorous and will eat just about anything. To provide them with all the nutrients that they need to be healthy, you should provide them with a varied diet.

Their main diet should consist of dry foods, such as flakes, crisps, granules, algae wafers and pellets.

Protein foods should complement their diet. Live foods, frozen and freeze-dried foods are all good choices. Examples of such foods include, bloodworms, daphnia, tubifex, infusoria, earthworms and brine shrimp.

Ruby tetras have small mouths, so bigger foods should be cut into smaller pieces. This will avoid food getting stuck in their mouth, which can cause a lot of stress on the fish.

Generally, it is recommended that you fish your tetras twice a day. However, some people do it less often. 

As a rule of thumbs, you should only provide enough food to feed your tetras for 5 minutes. This is important because overfeeding can lead to diseases such as constipation and poor water quality.


Tetras are known to be peaceful fish. In fact, they can even be paired with Betta splendens, which are known to be aggressive. Tetras should always be in groups of 6 or more. Tetras is a schooling fish, which means that it feels more comfortable when paired with many of their own species. Failing to do so could be very detrimental for your tetras, especially in a community. You see Tetras are a schooling fish, which means they are most at ease when in large groups. Inside a community tank, this is especially important as it also helps them avoid predation from other species.


Breeding Ruby tetras can be done in an aquarium if the right steps are taken. Oftentimes, breeders can have trouble since females are not always willing to spawn. It all comes down to finding a breeding pair that is highly engaged with each other.

Before you begin the breeding process, prepare a separate tank with enough plants to give shelter to the fish. The water should be slightly acidic, namely between a pH level of 6 to 6.5. The water should be soft, with dGH below 1.5.

You may also want to use a spawning mop to help the fish during the spawning stage.

When you have chosen a breeding pair, introduce them to the aquarium. The lights of the aquarium should be closed, and the aquarium covered to prevent light from entering.

A day or two later, begin to allow slightly more light into the aquarium daily. Eventually, the pair will spawn.

The eggs are sticky and will stick to plants, rocks and sometimes the aquarium glass.

Make sure to remove the parents from the aquarium as soon as you see the eggs. Oftentimes, the parents will eat their eggs if they are left inside the aquarium.

You should expect the eggs to hatch 24 to 36 hours later. Hatchlings will remain inside or near the eggs for a period of 24 hours, as they feed on the yolk sac.

When they are ready, the fry will begin to swim about the aquarium. At this point, you can begin to feed the fish with smalls foods like infusoria, or commercially available prepared foods for fish fry. Upon week 3, the fry should be big enough to other bigger foods like brine shrimp.

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