Mexican Tetra 101: Care, Lifespan, Facts & More!

Mexican Tetra

The Blind Cave Mexican Tetra, is a species of fish found in the caves of Mexico.

They are unique for their lack of pigmentation, which gives them their characteristic pale color.

These fish have poor vision and rely heavily on their other senses to navigate their environment.

Because they are blind, they use echolocation to communicate with one another and find food.

This guide will discuss everything about this interesting fish, from their origin and habitat, to how to breed them.


Scientific NameAstyanax Mexicanus
Common NameBlind cavefish, Mexican tetra, and Blind cave tetra
OriginThe caves of Mexico
Minimum Tank Size20 gallons
LengthThe average adult length is 3.5 inches (8.9 cm)
Ease of CareModerate
pH6.5 – 8.0 pH
TemperatureBetween 68-77°F (20–25°C)
AggressionPeaceful fish that can become more aggressive when they grow older.
LifespanThey can live for 3 to 5 years.

 Blind Cave Mexican Tetra Origins

The blind cave Mexican tetra, also known as the Mexican cavefish, is native to central and eastern Mexico. It is found in Texas’s rivers, ponds, creeks, and springs.

The Blind Cave Tetras bred in captivity are all descended from specimens collected in the Cueva Chica Cave in the southern Sierra del Abra system in 1936.

These were given to an aquarium company in Texas, which distributed them to aquarists immediately. Since then, the species has been bred in captivity and is now widely available.

What Are the Features of  Blind Cave Mexican Tetra?

1. Appearance

The Mexican tetra is a tiny fish with a bland appearance, but it hides a thrilling story of evolution, in which distinct populations have evolved diverse features and habitats, resulting in much debate over taxonomy.

One species is a silver-colored surface dweller with a black band that runs down each side to the tail.

Some individuals’ tails and lower fins might be colored yellow or red.

The other form has adapted to live in caves, resulting in a loss of color and, perhaps most significantly, the loss of sight.

The Mexican tetra is distinguished by a forked tail, a tiny dorsal fin, and an anal fin with tiny hooks on breeding males.

The most notable feature of this fish is its complete lack of eyes, a trait that has evolved due to its adaptations to life in complete darkness.

Blind Cave Mexican Tetra Have No Eyes?

Blind cave mexican tetras are born with eyes, but they gradually lose their sight as they mature. This is thought to be an adaptation to their natural habitat, which is dark and murky.

2. Color

The natural coloration of this fish is silvery-gray, but it can also be found in a translucent pink hue.

This color change is thought to be due to different levels of carotenoids in the diet.

3. Length

The blind cave Mexican tetra (Astyanax mexicanus) can grow to 5 inches, though some only reach 3 inches in adulthood. Size variations occur both in the wild and in captivity.

4. Lifespan

Blind cave Mexican tetras have a lifespan of up to five years. However, the fish only live such long lives if their tank conditions are stable and clean.

Is Blind Cave Mexican Tetra Hardy?

Yes, Blind Cave Mexican Tetras are pretty hardy. Just make sure to provide them with plenty of live plants and natural accessories in their aquarium to feel comfortable.

Blind Cave Mexican Tetra  Availability

Mexican tetras are not commonly found in pet stores, but you can purchase them from some online retailers.

It is essential to buy Mexican tetras from reputable breeders like Arizona Aquatic Gardens, as there is no guarantee of the health and care of tetras sold by anonymous sellers online.

The average price of a Mexican tetra from an online pet store is around $5.99, although costs may vary depending on the seller.

It’s critical to be wary of breeders who sell Mexican tetras for less than $5 since they may not have been bred in optimal circumstances and are more likely to become sick.

How to Care for  Blind Cave Mexican Tetra?

1. Tank Size

These species have small sizes, so they do not need a large tank. At least 20 gallons of water per individual will ensure enough area to swim and play comfortably.

2. Temperature

The ideal temperature for Blind Cave Mexican Tetras is 68-77 degrees Fahrenheit (20-25 degrees Celsius).

3. PH Level

These fish require a slightly higher pH than most other tetra species, typically between 6.5 and 8.

4. Lighting

This fish is adapted to complete darkness, so it does not require any special lighting. In fact, too much light can be harmful to these fish.

However, if you have plants in your aquarium, you will need to provide them with lighting. Just make sure not to provide so much light that it disturbs the Blind Cave Mexican Tetras.

5. Filters

It is essential to have a good filter because the Blind Cave Mexican Tetra requires clean water.

A canister filter or an external hang-on-back filter will work well for this fish. Be sure to get a filter rated for at least twice the size of your aquarium.

For example, if you have a 10-gallon tank, you should get a filter rated for at least 20 gallons.

Another essential part of keeping your Blind Cave Mexican Tetra healthy is to do regular water changes.

It would help if you did a water change of at least 10% each week. You can do a 20-25% water change every other week if you have a larger tank.

Be sure to use a dechlorinator when adding new water to the tank.

6. Tank Decoration

Mexican tetras live in slow-flowing water in the wild, so it’s important to replicate this environment in their tank.

The substrates for their tank are soft sand and gravel, which can be mixed to create a more natural look.

The middle section of the tank should be left transparent so the fish can swim around freely.

To decorate the aquarium, use natural plants, bits of driftwood, and rocks.

Avoid water bubblers, as fast-moving water can stress the fish. Instead, install a high-quality filter to keep the water clean and fresh.

With a little bit of planning, you can create the perfect environment for your blind cave Mexican tetra.

By providing them with suitable habitat, you’ll be able to enjoy watching these beautiful fish swim in your home aquarium for years to come.

Blind Cave Mexican Tetra  Diet

These fish are opportunistic feeders in the wild and will eat whatever meat and vegetation, including small insects, crustaceans, and plant matter.

In captivity, Blind Cave Mexican Tetras should be fed fish food flakes and pellets that sink to the bottom of the tank.

You can also supplement their diet with freeze-dried or live brine shrimp, mosquito larvae, and bloodworms two or three times per week as a treat.

Feed them twice daily, preferably in the morning and evening.

Avoid overfeeding your fish as this can lead to health problems. Also, avoid feeding them food that floats at the top of the tank as they are bottom feeders and may not be able to reach it.

Blind Cave Mexican Tetra Compatibility

It’s essential to understand their needs and compatibility with other fish before you add a Blind Cave Mexican tetra to your home aquarium.

Blind Cave Mexican Tetras are peaceful fish that spend most of their time in the mid-section of the tank.

They are usually well-behaved fish, but Mexican tetras can show aggression towards tank mates if kept in small tanks with unsuitable fish.

These tetras nip the fins of other tank mates and swim into other fish to show dominance.

Mexican tetras should share a tank with peaceful fish that won’t get in the tetras’ way.

Blind Cave Mexican Tetra can be kept with the following fish:

  • Barbs
  • Gouramis
  • Guppies
  • Mollies
  • Platies
  • Other tetras.

Blind Cave Mexican Tetra can’t be kept with the following fish:

  • Snails
  • Shrimps
  • Other crustaceans.

Blind Cave Mexican Tetra  Gender Difference

There is no external difference between the sexes of Blind Cave Mexican Tetras.

However, when the females are full of eggs, they tend to be wider when viewed from above. This is the only way to tell the sexes apart.

Blind Cave Mexican Tetra Breeding

Blind Cave breeding is a popular choice for those who want to breed fish, as they are relatively easy to breed in captivity.

If you are interested in breeding Blind Cave Mexican Tetras, there are a few things you will need to do to ensure success.

You will need to purchase a group of at least six fish, as they are schooling fish and do not do well independently. It is best to have two females for every male.

You will also need to set up a breeding tank at least 20 gallons in size. The tank should be well-filtered and have plenty of hiding places for the fish.

Live plants are a good idea, as they will help oxygenate the water and provide shelter for the fry (baby fish) once they are born.

When the time comes to spawn, the female fish will lay many adhesive eggs on the plants or decorations in the tank. The male fish will then fertilize the eggs.

Once the eggs are fertilized, they should be left in the tank, as the parents will not eat them.

The fry will hatch within a week and free-swim a few days later.

At first, they will live off of their egg sacs, but you will need to start feeding them baby brine shrimp or powdered fish food after a few days.

As the fry grows, it should be moved to a larger tank.

Once they reach adulthood, they can be moved back into the main tank with the other fish.

Possible Diseases and Prevention

While Blind Cave Mexican Tetras are generally hardy fish, some diseases can affect them.

One of the most common is White Spot Disease, caused by a parasite. This disease is characterized by white spots on the fish’s bodies and fins.

Another disease that can affect Blind Cave Mexican Tetras is Hole in the Head Disease.

This disease is caused by bacteria and is characterized by pits forming on the fish’s head.

Prevention is the best medicine for diseases and Blind Cave Mexican Tetras.

Be sure to quarantine new fish before adding them to your tank. Also, keep your tank clean and free of debris. A sound filtration system is also a must since it will help to keep the water quality high.

If you suspect your fish are sick, take them to a qualified veterinarian for treatment.

Last Words

This little fish is a big favorite among aquarium enthusiasts, and it’s not hard to see why!

The Blind Cave Mexican Tetra is a lively and beautiful fish perfect for adding some color and excitement to your tank.

If you’re planning on keeping one, make sure you acquire a friendly adult and feed and take care of it until it’s ready to breed.

We hope you’ve enjoyed learning about these methods as much as possible. If you still have questions, please leave them in the comment section below