Bloodfin Tetra: Species Overview

Category: Tetra

Common Names: Bloodfin Tetra

Scientific Name: Aphyocharax anisitsi

Family: Characidae

Minimum Tank Size: 20 Gallons

Care Level: Easy

Temperament: Peaceful

Max Size: 2 Inches

Temperature: 72-80 F

pH: 6.0-8.0

Tank Level: Bottom to Middle

Colors: Tan, Red, Green

Diet: Omnivore

Breeding: Moderate

Left Side of Bloodfin Tetra

Bloodfin Tetra: Species Overview

Bloodfin tetras are striking small schooling fish that are popular for adding color to a tank without being too overpowering. They’re also active, making them fun to watch as they dash around their aquarium.

These fish are relatively hardy, making them excellent for beginners who are learning the ropes of fish keeping.

That said, you must maintain specific water parameters to keep bloodfin tetras in good health.

Distinguishing Features

You’re spot-on if you pictured a bloodfin tetra with red fins. Deep red ray fins and a tail are the most iconic characteristics of the species.

However, the tips of their fins and tails are translucent, making their length a trick of the eye since they seemingly stop at the red color. Nevertheless, the bloodfin tetra’s fins and tail are short and well-proportioned for its size.

The rest of the tetra’s body is a shiny silver color. When the light catches right, these fish have an iridescent shine with some blue to green colors.

Bloodfin tetras have a torpedo shape, with the larger section of their body being around their stomachs and heads.

There aren’t too many variations within the species. Still, males usually have brighter red coloring than females.

Bloodfin Tetra with Rock and Plant in Background


Bloodfin tetras come from a specific region of South America—the Paraná River Basin. It is the second largest river after the Amazon, and expands across the following four countries:

  • Brazil
  • Paraguay
  • Bolivia
  • Argentina

You can also find bloodfin tetras living in the wild in other countries in the Amazon Basin.

These fish prefer slower-moving acidic water that contains lots of plant vegetation. Since bloodfin tetras live in the middle to the upper portion of the water column, they rely on plants growing from the substrate and those that float for shelter.

The substrate in their natural habitat is dark with rotting organic matter mixed with sand and some rocks.

As a result, these freshwater fish can handle cloudy water, although they enjoy clearer conditions outside of the rainy season.


Bloodfin tetras grow to two inches as adults.

Males and females typically grow to equal lengths. However, males tend to have a slimmer appearance than their female counterparts.


Bloodfin tetras have an average lifespan of five to eight years old.

While genetics will play a role in how long your tetras will live, you can improve their chances of a long life by providing them with ideal tank conditions and high-quality food.


Bloodfin tetras are easier to tell apart gender-wise than many other types of tetras. As mentioned earlier, males typically have more vibrant colors than females.

You may also notice gill glans and hooks on a male’s anal fins. But these features aren’t present in all males, so they’re not the most reliable way to determine gender.

Females typically have a rounder appearance, particularly around their bellies. It’s even easier to see this distinction when a female becomes pregnant with eggs.

Bloodfin Tetra in Front of Plant


Bloodfin tetras are friendly fish that usually get along well with each other and other species of peaceful tank mates of a similar size.

Still, these fish have a pecking order, so you’ll sometimes see them break out into small groups within their school. That’s especially the case if there’s a small tetra in the tank relative to the other group’s average size.

Bloodfin tetras will also take advantage of the opportunity to nip the fins of other fish, particularly during feedings or if you have slow-movers in the tank with long fins.

There isn’t a noticeable difference between males and females in terms of aggression. Instead, it’s the size that determines who is more likely to be adversarial and those that will be towards the bottom of the fish totem pole.

Although it might sound like bloodfin tetras are aggressive based on these details, they’re genuinely community-oriented fish. So, as long as you take a few basic precautions to pair them with suitable tank mates, you can expect them to behave peacefully.

Tank Parameters

Setting up a tank is always exciting. But before you throw tons of decorations in it and fill it with water, be mindful of what your bloodfin tetras will need to thrive.

Minimum Tank Size

You should choose a tank that’s at least 20 gallons so you can comfortably keep five to seven bloodfin tetras.

Should you wish to have a larger school of tetras or include other tank mates in the aquarium, you’ll need to increase the tank size.

Water Parameters

Below are the water parameters you’ll need to ensure your bloodfin tetras remain in their best health.


Bloodfin tetras like warm water, although they can tolerate cooler temperatures than many other species of tetra. You should keep their water between 70°F to 82°F.

That said, we recommend keeping the temperature in the mid to upper 70s. Doing so will keep your fish extra happy and give them wiggle room should the water temperature fluctuate.


You’ll need to keep your bloodfin tetra’s water pH between 6.0 and 8.0.

That means if you want to stick with the middle of the range, you can keep the water at a neutral pH of 7.0. Again, bloodfins are unique from many other kinds of tetras, given that they can tolerate more alkaline water. However, they prefer water that leans toward mildly acidic.

Group of Bloodfin Tetras


Never place bloodfin tetras in a saltwater tank, for they’ll soon die from being unable to filter the salt out of their system.

Nevertheless, small amounts of aquarium salt have a place in certain freshwater tropical fish tanks.

For instance, if your bloodfin tetras have parasites, a bacterial infection, or look otherwise unwell, salt may help improve their immune system.

Tank Setup

With your aquarium water ready to receive bloodfin tetras, it’s time to explore how to set up your aquarium so that it’s inviting and comfortable for your fish.


Since bloodfin tetras live in the middle of the tank, they rarely visit the substrate. Therefore, it’s more important to choose a darker color substrate than to concern yourself with the type you use.

That’s because bloodfin tetras have dark brown to black substrates in the wild, thanks to decaying plants in the riverbed.

So, dark sand and fine gravel will be the most suitable options for a bloodfin tetra.


Decorations are a nice touch in a bloodfin tetra tank for the fish and owner. We encourage you to use natural decor that your tetras would typically encounter in the wild.

Examples include:

  • Caves
  • Rocks
  • Driftwood
  • Sunken wood

Since bloodfin tetras live in the middle part of the water column, try to select at least one decoration that they’ll have easy access to. An excellent option is a large piece of wood.


Live plants are the most important decoration you can add to your bloodfin tetra’s tank.

These fish live in densely vegetated areas in the wild, using plants as shelter from predators and bright sunlight.

Some excellent plants for bloodfin tetras include:

  • Broadleaf anubias
  • Narrow-leaf anacharis
  • Water lettuce
  • Java moss

While offering your fish areas with dense plant growth in their tank is important, it’s equally essential that your bloodfin tetras have enough space to school in groups.

So, be mindful of balancing plants with open water.

VGW2006 [Public Domain]


Bloodfin tetras don’t require much lighting, but many other tropical fish do.

With that in mind, if you have an aquarium light, keep it on a medium to a dim setting. As mentioned earlier, bloodfin tetras will use plants to escape bright lights.

So, be sure the plants grow tall enough so that they block out significant portions of an aquarium tank light.


A high-quality filter system is essential for all bloodfin tetra tanks. Not only will these filters keep your tank visually clean, but more importantly, they remove invisible toxins like ammonia and nitrite.

Since bloodfin tetras don’t originate from water with strong currents, purchase a filter that won’t generate a lot of movement.

At a minimum, select a filter with biological and mechanical properties. Chemical filters are also useful for keeping your bloodfin tetra’s water in tip-top shape.


Unlike certain tetra species, many fish keepers can get away without having a heater for their bloodfins. That’s because these tetras have a higher-than-average tolerance for cooler water.

Nevertheless, if your home’s temperature ever dips below 70°F, a heater is a must.

Even if you keep your house warmer, using a heater is still a good idea to help the water maintain a consistent temperature.


Bloodfin tetras are omnivores that appreciate a varied diet for happiness and health.

Some of the best foods to give your bloodfin tetras include:

  • Brine shrimp
  • Fish flakes
  • Spinach
  • Fish pellets
  • Bloodworms

It’s vital to monitor the amount of food you give your bloodfin tetras. Otherwise, these precocious fish will gladly eat their way to obesity, and excess food will cause additional toxin build-up in the water.

The best way to feed your bloodfin tetras is to offer them food two to three times per day. After two or three minutes pass, remove all remaining food to avoid overeating.


Breeding bloodfin tetras is easy, and you should do so in a separate breeding tank to maximize the chances of success.

Bloodfin tetras become triggered for breeding when you set the tank light on a low setting, there are lots of plants, and they eat a diet high in protein.

Be sure to keep a lid on the breeding tank, for it’s common for females to jump out of the water as she lays eggs.

Females lay anywhere from 300 to 500 eggs, and the males will fertilize them. Once you see eggs in the breeding tank, remove all fish.

Doing so gives the eggs a higher chance of survival since the parents won’t have the opportunity to eat them.

Within a few days, you’ll have baby fry and can feed them small brine shrimp and fine flake food.

Common Diseases

Caring for bloodfin tetras is straightforward once you know the basics. But even so, they can come down with illnesses.

Below are some of the most common diseases these fish face.


Ich is a persistent, small white parasite that burrows beneath a bloodfin tetra’s scales. It causes tetras to become itchy, so you’ll see them rubbing against hard objects.

Introducing a new, infected fish into your tetra’s aquarium is the most common way that ich arrives. You can kill this parasite with a multi-week treatment of ich medicine and water changes.

Ammonia Poisoning

Ammonia poisoning is a life-threatening condition that results from poor water quality. Not making partial water changes or inserting a new filter media in the tank are the most typical causes of it.

Bloodfin tetras with ammonia poisoning often move to the water’s surface, gasp for air, and have gills that turn red. You should change the water immediately upon seeing such symptoms.

Swim Bladder Disease

Swim bladder disease is when a bloodfin tetra’s swim bladder becomes enlarged, causing them to have trouble remaining upright in the water.

It can result from several triggers, such as parasites, overeating, and constipation. The treatment for swim bladder disease varies according to the cause, but putting your tetra on a temporary fast and adding aquarium salt to the tank can sometimes resolve the problem.

Potential Tank Mates

Before adding tank mates to your aquarium, you will need to ensure that you have a group of at least five to seven bloodfin tetra. Without sufficient members of their own species to cohabit with, your fish is at risk of suffering from stress and other emotional health issues.

When choosing your tetra’s tank mates, be sure that the fish are similar in size, have short fins, and have friendly personalities. Aggressive or larger species could distress or even harm your tetras.

Some of the best tank mates for bloodfin tetras include:

  • Bristlenose pleco
  • Pictus catfish
  • Cory catfish
  • Neon tetra
  • Ember tetra

These are just a tiny sample of the many fish species that do well with bloodfin tetras.