Mexican Tetra Care Guide: Appearance, Size, Diet & All | 2024

The Mexican Tetra is a freshwater fish that is native to Mexico. It is a popular fish for aquariums and has a bright, colorful appearance. The Mexican Tetra is a peaceful fish that does well in a community tank.

Part of the Characidae family, the Mexican Tetra (Astyanax mexicanus) is also the blind cave fish because it is sometimes found in caves devoid of light.

Native to the Nueces and Pecos Rivers in Texas and the Rio Grande in Mexico, the Mexican Tetra is a hardy fish that can withstand various water conditions.

The Mexican Tetra comes in two forms — the cave and the surface. The cave form is blind and has pale skin, while the surface form has eyes and brightly-colored skin.

This guide will examine everything you need about Mexican Tetras, including their appearance, habitat, diet, and care requirements.

So without further ado, let’s dive in and learn about Mexican Tetras!

Species Summary

Scientific name:	Astyanax mexicanus
Common names:	Mexican Tetra, blind cavefish, Rio Grande tetra
Family:	Characidae
Color:	Silvery and gray or translucent pink
Origin:	Mexico and Texas
Adult size:	3 to 5 inches
Life expectancy:	Up to 4 years
Habitat:	Rivers and streams with slow-moving water
Behavior:	The Mexican Tetra is a peaceful fish that does well in a community tank
Minimum tank size:	20 gallons
Temperature range:	68°-77°F (20-25°C)
pH range:	6.5 to 8.0 ph
Water type:	Freshwater
Water hardness:	30 dGH Soft to medium
Activity Level:	Moderately active
Sociability:	Moderately social
Tankmates:	The Mexican Tetra does well with other peaceful fish.
Gender Differences:	The male Mexican Tetra is usually more significant than the female and has a more pointed anal fin.
Temperament:	Mostly peaceful with some aggressive tendencies
Care Level:	Moderate
Compatibility:	Good with other peaceful fish
Breeding method:	Egg-layer
Diet:	The Mexican Tetra is a carnivore
Feeding Frequency:	2 to 3 times per day

The Mexican Tetra is a peaceful fish that does well in a community tank. It is a moderately active fish that is not overly social.

The male Mexican Tetra is usually more significant than the female and has a more pointed anal fin.

They have been classified as a “least concern” species by the IUCN Red List. The cost of a Mexican Tetra varies depending on the type of fish and where you purchase it.

A single Mexican Tetra can cost anywhere from $4 to $10. A group of six Mexican Tetras can cost between $10 and $30. But, if you want to purchase a cave from Mexican Tetra, they can cost up to $50.

Mexican Tetra Appearance

Mexican Tetras come in two forms and look different depending on their habitat — the cave and surface. The cave form is blind and has pale skin, while the surface form has eyes and brightly-colored skin.

The Mexican Tetra has a long, slender body with a pointed head. They are silvery and gray in color or translucent pink.

The males have a more pointed anal fin than the females. They are popular fish for aquariums because of their colorful appearance.

They are available in various colors, including blue, green, orange, and red. Female Mexican Tetras have pointed ventral fins, while males have more rounded ventral fins.

The body of a Mexican Tetra is compressed laterally, and they have a single dorsal fin.

Females are also usually smaller in size than males. So, if you are trying to have sex with Mexican Tetras, look for the difference between their anal fins and ventral fins.

Mexican Tetra Size & Growth Rate

The size of a Mexican Tetra can range from 3 to 5 inches. The male Mexican Tetra is usually more significant than the female and has a more pointed anal fin.

The growth rate of a Mexican Tetra is relatively fast. They can reach their full size within 6 to 12 months.

Mexican Tetra Lifespan

Mexican Tetras have a lifespan of up to 4 years.

However, it is essential to note that their Lifespan can be shortened if they are not kept in optimal conditions.

Mexican Tetra Behavior & Temperament

Mexican Tetras are peaceful fish that spend most of their time near the bottom of the tank. They are known to be somewhat shy, so they should be kept in groups of six or more. 

They are not known to be territorial and get along well with other peaceful fish. They are usually well-behaved, but they may nip at the fins of other fish if they feel stressed. These tetras nip the fins of other fish to relieve stress. 

Look out for signs of aggression and stress in your fish. Removing the fish from the tank is best if you see any of these signs.

Although the fish are most active during the day, they may become more active at night if the tank is dimly lit. 

You should provide plenty of hiding places for your fish to feel safe. Some good options include caves, plants, and driftwood.

Mexican Tetras Breeding

Mexican Tetras are not difficult to breed in captivity. They will often spawn without any intervention from the Aquarist. However, there are a few things that you can do to increase your chances of success.

The first thing you need to do is to set up a breeding tank. The tank should be at least 20 gallons and have a sandy substrate.

The water should be clean and well-filtered. The temperature should be between 68° to 77° Fahrenheit.

It is also a good idea to add some plants to the tank. This will provide the fry with hiding places and help oxygenate the water.

The next thing you need to do is to select a pair of healthy fish. The female should be a little larger than the male. The fish should also be roughly the same age and size.

Once you have selected a pair of fish, you must condition them for breeding. This can be done by feeding them various live and frozen foods. You should also perform regular water changes during this time.

When the fish are ready to breed, the female will lay a few hundred eggs on the plants in the tank. The male will then fertilize the eggs. The fry will hatch after 3-5 days.

The fry should be fed a diet of live and frozen foods. They can also be given finely ground flake food or baby brine shrimp.

It is essential to provide plenty of places for the fry to hide. Otherwise, they may be eaten by their parents or other fish in the tank.

Mexican Tetra Care Guide

Mexican Tetras have a moderate care level. They are peaceful fish that does well in a community tank. However, they can be aggressive towards other tetras.

Mexican Tetras are relatively easy to care for if the tank is kept clean and the water quality is good.

They are native to slow-flowing and highly-oxygenated waters in Mexico and Texas. They can be found in cave pools, spring-fed creeks, and rivers in the wild.

They are carnivore fish, and their diet should consist of live, frozen, or freeze-dried foods. Feed them 2 to 3 times per day.

We will discuss everything you need about Mexican Tetra care, including diet, tank setup, and compatibility.

Also Read: Bellus Angelfish Care: Appearance, Size, Lifespan

Mexican Tetras Food & Diet

Mexican Tetras feed on whatever meat and small insects they can find in their natural habitats. Their diet consists mainly of small crustaceans, insect larvae, and zooplankton in the wild. 

In captivity, they should be fed a diet of high-quality flakes or pellets and live or frozen foods. Good options for live or frozen foods include brine shrimp, bloodworms, and daphnia. It is essential to offer various foods to ensure your fish get all the necessary nutrients.

These fish are bottom feeders, meaning they spend most of their time near the bottom of the tank. It is best to target-feed them when feeding them so they get enough to eat. 

For snacks, you can give them blanched vegetables like zucchini, broccoli, or spinach.

Diet Foods To Avoid

There are a few foods that you should avoid feeding your Mexican Tetra.

These include:

• Foods high in fat: foods that are high in fat can cause health problems for fish.
• Feeder fish: Feeder fish can sometimes carry diseases that can be passed on to your fish.
• Spicy foods: Spicy foods can cause digestive problems for fish.

It is best to avoid these foods altogether to ensure the health of your fish.

Tank Size

The minimum tank size for a Mexican Tetra is 20 gallons. However, it is recommended that you have a 30-gallon tank or more significant. This will give them enough room to swim and provide a good environment.

Water Parameters

The water temperature should be between 68°F to 77°F. The pH level should be between 6.5 to 8.0. The hardness of the water should be between 4 to 8 dGH.

The specific gravity should be between 1.020 and 1.025. And the water should be well-oxygenated.

To help maintain the water quality, you should do a weekly water change of 20%.

Filtration

Mexican Tetras are hardy fish and can tolerate various water conditions. However, it is essential to maintain good water quality in their tank.

A sound filtration system is necessary for keeping the water clean and the tetras healthy.

When choosing a filter for your tank, make sure it is rated for at least twice the volume of your tank. For example, if you have a 30-gallon tank, you will need a filter rated for at least 60 gallons.

Using a filter with an adjustable flow rate is also a good idea. This way, you can control the water flow in the tank and ensure it is not too strong for the tetras.

Some recommended filters for a Mexican Tetra tank are:

• The Aqua Clear 50 Power Filter
• The Fluval Canister Filter
• The Marineland Penguin Power Filter

Heating

The water temperature for a Mexican Tetra tank should be between 68°F to 77°F. If your home’s temperature is below this range, you must use a heater to maintain the correct water temperature.

It is recommended that you use an aquarium heater with an automatic shut-off. This way, if the water temperature gets too high, the heater will turn off automatically and prevent the water from getting too hot.

Some recommended heaters for a Mexican Tetra tank are:

• The Hydro Plus Aquarium Heater
• The Aqueon Submersible Aquarium Heater
• The Tetra Aqua aquarium Heat Pump

Plants

Mexican Tetras are not picky eaters and will eat most types of plants. However, they do prefer plants that are soft and have a high moisture content.

Some recommended plants for a Mexican Tetra tank are:

• Hornwort
• Java Moss
• Water Sprite
• Anacharis

Lighting

The lighting for a Mexican Tetra tank does not need to be very bright. A low to moderate light level is sufficient.

If you are using live plants in your tank, you must provide them with a light source so they can photosynthesize. However, the light does not need to be very strong.

Some recommended lights for a Mexican Tetra tank are:

• The Aqua Culture Fluorescent Aquarium Hood
• The Tetra LED Aquarium Kit
• The Aqueon Modular LED Aquarium Light

Fertilizers

If you are using live plants in your tank, you will need to provide them with a source of nutrients. This can be done through the use of fertilizers. Fertilizers can be added to the water, or they can be applied directly to the plants.

Some recommended fertilizers for a Mexican Tetra tank are:

• The Seachem Flourish Comprehensive Plant Supplement
• The API Leaf Zone Aquarium Plant Food
• The Tetra Plant Food Tablets

Co2 Systems

If you are using live plants in your tank, you will need to provide them with a source of carbon dioxide. This can be done through the use of a CO2 system.

A CO2 system can be either DIY or commercial.

Some recommended CO2 systems for a Mexican Tetra tank are:

• The Fluval Pressurized CO2 Kit
• The Aqua Jelly DIY CO2 Kit
• The GLA Aquariums CO2 Regulator

Water Conditioners

It is essential to use a water conditioner in your Mexican Tetra tank. This will remove harmful chemicals from the water and make it safe for your fish.

Some recommended water conditioners for a Mexican Tetra tank are:

• The Seachem Prime Water Conditioner
• The API Stress Coat+ Water Conditioner
• The Tetra Aqua Safe Plus Water Conditioner

Substrate

The substrate is the material you put at your tank’s bottom. It can be either live or artificial.

Some recommended substrates for a Mexican Tetra tank are:

• The Tetra Aqua Safe Plus Planting Medium
• The Fluval Plant and Shrimp Stratum
• The Aqua Design Amano Shrimp Soil

Decorations

It is essential to provide your Mexican Tetra with various places to hide. This can be done through the use of decorations.

Some recommended decorations for a Mexican Tetra tank are:

• The Zoo Med Aquatic Decorations
• The Penn Plax Aquarium Decorations
• The Fluval Sea Decorations

Other Tank Accessories

You may need a few other things for your Mexican Tetra tank.

These include:

• Aquarium Thermometer: This is necessary to monitor the water temperature.
• Aquarium Test Kit: This is necessary to test the water quality. It will help you to keep the water clean and clear.
• Air Pump: This is necessary to provide oxygen to the water.
• Ph Meter: This is necessary to test the pH of the water.
• TDS Meter: This is necessary to test the total dissolved solids in the water.

As you can see, there are a variety of things that you will need for your Mexican Tetra tank. These include a CO2 system, water conditioner, substrate, decorations, and other tank accessories. Following these guidelines will create a happy and healthy environment for your fish.

Water Changes

It is essential to do regular water changes in your Mexican Tetra tank. This will help to keep the water clean and clear.

It also helps to remove any harmful chemicals that may be in the water.

The recommended water change schedule for a Mexican Tetra tank is as follows:

• Weekly: 20% water change
• Monthly: 50% water change

To do water changes, you will need the following:

• A water bucket is necessary to hold the water you will remove from the tank.
• A gravel vacuum is needed to remove the debris from the bottom of the tank.
• A siphon is necessary to remove the water from the tank.

The steps for performing a water change are as follows:

• Remove the lid from the tank.
• Place the gravel vacuum in the tank and turn it on.
• Vacuum the debris from the bottom of the tank.
• Please turn off the gravel vacuum and remove it from the tank.
• Place the siphon in the tank and turn it on.
• Siphon the water from the tank into the bucket.
• Turn off the siphon and remove it from the tank.
• Fill the tank with fresh water.
• Replace the lid on the tank.

Cleaning The Tank

It is essential to clean the tank regularly. This will help to remove any algae or build-up that may be present.

To clean the tank, you will need the following:

• A water bucket is necessary to hold the water you will remove from the tank.
• A sponge is necessary to scrub the inside of the tank.
• A siphon is required to remove the water from the tank.

Cleaning The Filter

It is essential to clean the filter regularly. This will help to remove any build-up that may be present.

To clean the filter, you will need the following:

• A water bucket is necessary to hold the water you will remove from the tank.
• A water conditioner is needed to remove the chlorine from the water.

The steps for cleaning the filter are as follows:

• Remove the filter from the tank.
• Rinse the filter in the water bucket.
• Fill the tank with fresh water and add the water conditioner.
• Place the filter back in the tank.

Testing The Water

It is essential to test the water regularly. This will help you to keep the water clean and clear.

To test the water, you will need the following:

An aquarium test kit is necessary to test the water quality.

The steps for testing the water are as follows:

• Test the pH of the water.
• Test the ammonia levels in the water.
• Test the nitrate levels in the water.
• Test the nitrate levels in the water.
• Test the hardness of the water.

Mexican Tetra Common Possible Diseases

They are generally hardy and do not succumb to diseases often. However, there are a few things that can go wrong.

The most common health problems include:

Parasites

Parasites are the most common health problem in Mexican Tetras. They can be introduced to the tank through infected fish or live foods. Symptoms of parasites include lethargy, loss of appetite, and erratic swimming.

If you suspect your fish have parasites, you should take a sample of their feces to your local aquarium store for testing. Treatment for parasites typically involves medication that is added to the water.

• Bacterial Infections
• Fungal Infections  
• Ich  
• Fin Rot  
• Swim Bladder Disease
• Gill Flukes

Signs That Your Mexican Tetra Is Sick

There are a few signs that your Mexican Tetra may be sick.

These include:

• loss of appetite
• lethargy
• weight loss
• darkened coloration
• clamped fins
• fragile fins
• oozing eyes
• bulging eyes

You must immediately save your fish if you notice any of these signs.

Mexican Tetra Preventing Diseases

There are a few things that you can do to help prevent disease in your Mexican Tetra.

These include:

• Quarantine new fish before adding them to the tank.
• Clean the tank regularly.
• Test the water regularly.
• Feed your fish a healthy diet.
• Provide your fish with a stress-free environment.

Mexican Tetra Treatment And Medications Of Diseases

There are a variety of different medications available to treat diseases in fish.

These include:

• Anti-parasitic medication: This is used to treat parasites.
• Anti-bacterial medication: This is used to treat bacterial infections.
• Anti-fungal medication: This is used to treat fungal infections.
• Anti-inflammatory medication: This is used to treat inflammation.
• It is essential to follow the directions on the medication when treating your fish. Over-medicating can be just as harmful as not medicating at all.

Feeding Schedule

Mexican Tetras should be fed two to three times a day. It is best to target-feed them when feeding them so they get enough to eat.

They should be given a small amount of food in two minutes or less.

It is also essential to remove any uneaten food from the tank so that it does not contaminate the water.

Mexican Tetra Tank Mates

Mexican Tetras are peaceful fish that do well with other peaceful fish.

Some good tank mates include:

• Barbs
• Gouramis
• Tetras
• Rasboras
• Danios
• Loaches
• Catfish

These fish are all peaceful and do well in groups. They should be kept in tanks of at least 20 gallons.

Mexican Tetra Fish To Avoid

It is best to avoid keeping these fish with larger and more aggressive fish. Some fish that should be avoided include:

• Bettas
• Dwarf cichlids
• Guppies
• Mollies
• Platies
• Swordtails

These fish are all known to be aggressive and may bully or harass your Mexican Tetras.

It is best to avoid keeping these fish together in the same tank.

How To Choose A Healthy Mexican Tetra

When choosing a Mexican Tetra, choosing an active fish with a bright coloration is essential. The fish should also be free of any visible signs of illness. Choosing a fish from a reputable breeder or store is also a good idea.

Once you have chosen a healthy fish, it is essential to acclimate the fish to its new environment. This should be done slowly over some time. This will help the fish to adjust to its new home and reduce the risk of stress.

The Importance Of A Healthy Diet

A healthy diet is essential for all fish but especially for Mexican Tetras. This is because these fish are susceptible to changes in their environment. A sudden change in diet can cause stress and health problems.

It is essential to offer various foods to ensure your fish get all the necessary nutrients. A diet that is too high in fat can cause health problems for fish. Feeder fish can sometimes carry diseases that can be passed on to your fish. Spicy foods can cause digestive problems for fish.

It is best to avoid these foods altogether to ensure the health of your fish.

Advantages Of Having Mexican Tetra In Your Tank

The first advantage is that these fish are very peaceful. They will not bother other fish in the tank and get along well with other peaceful fish.

Another advantage is that these fish are straightforward to care for. They are not picky eaters, and they do not require special care.

Finally, these fish are straightforward to breed in captivity. They will often spawn without any intervention from the Aquarist.

Disadvantages Of Having Mexican Tetra In Your Tank

The first disadvantage is that these fish are timid. They may not come out much if other fish are in the tank.

Another disadvantage is that these fish are known to nip at the fins of other fish. This can be a problem if you have other fish in the tank that is not peaceful.

Conclusion

The Mexican Tetra is a good choice if you are looking for a peaceful and easy-to-care-for-fish. These fish are also straightforward to breed in captivity. However, you should be aware that these fish are timid and may not come out much if other fish are in the tank. Overall, the Mexican Tetra is a good choice for most Aquariums.

I hope you enjoyed reading this article. If you have any questions or comments, please leave them below.

Thanks for reading!