The Red Tail Barracuda Acestrorhynchus falcatus is one of about 15 or so characins belonging to the genus Acestrorhynchus. About half of these are found in the aquarium trade and are often referred to as Freshwater Barracuda. Of this group, the Red Tail Barracuda is the most regularly seen characin. It is also called the Spotted Cachorro, Dog Characin, and Amazon Cachorro.

It easy to see why species of Acestrorhynchus are called Freshwater Barracudas. The slender, elongated pike-shaped body and mouth full of sharp teeth say it all. Their body shape and large, conical teeth make them perfectly adapted to prey on other types of fish.

The term Freshwater Barracuda, however, is applied to several freshwater fish besides species of Acestrorhynchus genus. Livebearers of the genus Belonesox and the Gar characins of the genus Ctenolucius are two such groups, both of which are quick, sharp-toothed fish predators with streamlined bodies. One familiar species is the Freshwater Barracuda, or Hujeta Gar, Ctenolucius hujeta, a fierce predator that can reach up to 28 inches (70 cm) in length and is not usually kept in the home aquarium.

The Red Tail Barracuda has become a more common import in the last several years. Its slender, streamlined body features subtle, iridescent, silvery-gold hues that are complimented by beautiful red fins. This fish can grow to just shy of 11 inches (27 cm) in length and is a very highly evolved fish predator. The Red Tail Barracuda can consume any fish that is about half its size or smaller. Despite its size, appearance, and behavior, however, this fish is not a true barracuda but a Characin just like the more familiar tetras, hatchetfish, and pencilfish.

As long as you are willing to provide live fish as food, the Red Tail Barracuda makes a great aquarium pet. These fish do get pretty big, and being from a river environment, they need a lot of swimming space and clean, well-oxygenated water. Though a bit on the nervous side, they are very interesting, active fish. They do best with company and can be kept in a small school or with other companion fish. They will usually do very well with similarly-sized tankmates.

Scientific Classification


Red Tail Barracuda – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately Difficult
Minimum Tank Size:55 gal (208 L)
Size of fish – inches10.7 inches (27.20 cm)
Temperature:75.0 to 82.0° F (23.9 to 27.8&deg C)

Habitat: Distribution / Background

The Red Tail Barracuda Acestrorhynchus falcatus was described by Bloch in 1794. This species of Freshwater Barracuda is found in many rivers of Guyana, Suriname, and French Guiana, and throughout much of the Amazon and Orinoco River basins. This species is not listed on the IUCN Red List. Other common names it is known by are Spotted Cachorro, Freshwater Barracuda, Dog Characin, and Amazon Cachorro.

They are a riverine species, inhabiting clean, moderately flowing waters and are often found in schools. This formidable predator feeds exclusively on fish.

  • Scientific Name: Acestrorhynchus falcatus
  • Social Grouping: Groups – They are often found in schools.
  • IUCN Red List: NE – Not Evaluated or not listed


The Red Tail Barracuda has a slender, elongated pike-shaped body and a mouth full of needle-sharp teeth that are usually visible. It can get up to just about 11 inches (27 cm) and has a lifespan of 8 to 10 years. The body color is an iridescent, silvery-gold with a whitish area on the belly. The fins are transparent, sometimes displaying an orange-gold tint. The forked tail fin is a more colorful red with a large black spot at the base. Sometimes a black horizontal line develops, running from the eye to the tail spot.

  • Size of fish – inches: 10.7 inches (27.20 cm)
  • Lifespan: 10 years – They have a lifespan of 8 to 10 years.

Fish Keeping Difficulty

The Red Tail Barracuda is recommended for an aquarist with some fish keeping experience. They are relatively hardy fish. Though sensitive to organic pollutants and swings in water chemistry, water quality is not usually an issue if the aquarium is well maintained. The biggest difficulties with these fish are behavioral. These fast swimmers are prone to flightiness, so they need to be housed in a large aquarium with plenty of open swimming space. Also, they need to be fed life fish.

  • Aquarium Hardiness: Moderately Difficult
  • Aquarist Experience Level: Intermediate

Foods and Feeding

Red Tail Barracuda are carnivorous piscivores. They only eat live foods, and they prefer fish! There is a chance they can be trained to accept pre-killed fish, but you can’t count on that. Because live fish are what they like to eat, a good practice is to setup a small tank to keep a steady supply of small, live feeders available. You can also offer them earthworms, river shrimps, aquatic insects, and other good sized invertebrates. They may occasionally also take pellets for carnivores, Tubifex, and chopped meat.

  • Diet Type: Carnivore – This fish is piscivorous. They eat other fish almost exclusively.
  • Flake Food: No
  • Tablet / Pellet: No
  • Live foods (fishes, shrimps, worms): Most of Diet
  • Meaty Food: All of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Due to their diet of live foods, Red Tail Barracuda put a large bio load on the aquarium, so their tank needs ample filtration. Water changes of about 30 to 50% are needed every other week, depending on the bio load, to keep this fish happy and healthy.

  • Water Changes: Bi-weekly – Do a 30 to 50% water change every other week.

Aquarium Setup

These Freshwater Barracudas will spend most of their time near the middle of their home. They require a lot of space to thrive. Even though they don’t get all that large, a minimum tank size of 55 gallons is necessary to keep them in good condition. They also require good filtration with some current.

These very active fish need a great deal of open space for swimming, but they are also nervous and frighten easily. Provide a decor with some tall plants around the perimeter to help them feel secure and comfortable, but make sure their swimming area is open and unobstructed. They may jump, so the aquarium needs a good-fitting cover.

  • Minimum Tank Size: 55 gal (208 L)
  • Suitable for Nano Tank: No
  • Substrate Type: Any
  • Lighting Needs: Moderate – normal lighting
  • Temperature: 75.0 to 82.0° F (23.9 to 27.8&deg C)
  • Range ph: 6.0-7.5
  • Hardness Range: 8 – 15 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Middle – Freshwater Barracudas will swim near the middle of the tank.

Social Behaviors

In the wild, Red Tail Barracudas are often seen in groups. In captivity, this nervous fish frightens easily, and companions help them feel more secure. Keep them in a small school of Red Tail Barracudas, or other similar-sized occupants. They can be kept singly or in groups of 6 or more. A smaller group of 2 to 5 will lead to aggression and fighting.

Though they are not particularly aggressive, they will eat any fish small enough to fit into their large, toothy mouths. Good tankmates include other similar-sized fish, predators or otherwise, that are generally placid and ideally feed from the substrate. Characin species like Ctenolucius, Mylossoma and Silver Dollars or Myloplus make good tankmates. Other good companions include Geophagus spp., Plecostomus, and other bottom dwelling scavenger catfish.

  • Venomous: No
  • Temperament: Semi-aggressive
  • Compatible with:
    • Same species – conspecifics: Yes – This fish should either be kept singly or in groups of at least six to keep aggression levels low.
    • Peaceful fish (): Safe – As it is highly predatory, tankmates should be similarly sized.
    • Semi-Aggressive (): Monitor
    • Aggressive (): Threat – Aggressive tankmates should be avoided in all but the very largest tanks.
    • Large Semi-Aggressive (): Monitor
    • Large Aggressive, Predatory (): Threat
    • Monitor
    • Shrimps, Crabs, Snails: May be aggressive
    • Plants: Safe

Sexual differences

Females are plumper than males.

Breeding / Reproduction

In the wild, the Red Tail Barracuda begins reproduction with the onset of the rainy season. These egg scatterers discharge eggs and sperm into open water. Like other Characins, this free-spawning fish produces many fry. They have not yet been successfully bred in captivity. 

Specifially, the courtship and spawning of the Red Tail Barracuda has been observed in the aquarium, but no fry have been successfully reared. Frank Magallanes documented their breeding behavior and furnished the raw footage to Oregon State University, Neo-tropical Division, in 1994. The video shows the spawn occurring in midwater with the male swimming up and around the female in a type of figure 8 pattern while she remains stationary. Later spawning videos show the female releasing the  eggs.

For a chance at successfully breeding them, separate the males from the females and condition them heavily with live foods. Provide a large spawning tank. This can be a low aquarium, filled 3/4 full with clean, aged water, and with an initial temperature that matches their regular aquarium. The bottom can be sandy or bare, but it should be lined with a dense foliage.

Introduce the males and females into the prepared tank, with a ratio of 2 males per female. Gradually increase the temperature to around 80° F (27° C) to stimulate breeding. As with other Characins, covering the top with a towel will create a darkened environment to help trigger the spawn. Pairing should occur quickly below the surface of the water, with several eggs being shed at a time.

Remove the parents from the tank once the spawning is complete, or the parents will eat the eggs. The eggs should hatch in about 24 hours. Once free-swimming, the fry can be fed rotifers, Cyclops, or Artemia nauplii. The fry should be fed generously, at least 3 times a day, as newly hatched freshwater barracuda are cannibalistic and may otherwise eat each other. See Breeding Freshwater Fish: Characins for a general description of breeding processes, and see Fish Food for Fry for information about types of foods for raising the young.

  • Ease of Breeding: Unknown – This fish has yet to be bred in captivity.

Fish Diseases

Red Tail Barracuda are hardy and disease is not usually a problem in a well-maintained aquarium. That said, there is no guarantee that you won’t have to deal with health problems or disease. Anything you add to your tank can introduce disease. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so as not to upset the balance. Because these fish eat live foods, disease can be passed to them from their foods. To prevent this, quarantine live food before feeding.

Two types of disease tend to affect the Acestrorhynchus genus in captivity: parasites and fin rot. Both are extremely preventable and even treatable. A good thing about the Red Tail Barracuda is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if dealt with at an early stage. The best way to proactively prevent disease is to give your fish the proper environment and a diet of live foods that are parasite free.

As with most fish, Red Tail Barracuda are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. Aquarists should read up on common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Red Tail Barracuda is commonly available and moderately expensive, with price dependent on size.



 Acestrorhynchus falcatus (Image Credit: Vassil, Wikimedia Commons CC0 1.0 Universal)