Pacu Fish Care: Complete Guide for Beginners

Learn about Pacu fish, in this beginner’s guide, where you’ll find everything you need to know to set up and maintain a healthy, thriving environment for your Pacu fish. From tank setup and water requirements to diet and tank mates, we’ve got you covered.

giant pacu fish

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Pacu Fish Species Profile and Identification

Pacu fish, native to South American waters, are known for their impressive size and unique appearance. As part of the Characin family, which includes Piranhas, their relation is evident in their physical features.

However, Pacu fish are notably different from their aggressive cousins, often exhibiting a more docile temperament. These freshwater fish can be separated into several species, including the Red-Bellied Pacu (Piaractus brachypomus) and Black Pacu (Colossoma macropomum). Identifying your Pacu fish species is essential for providing proper care and diet.

  • Size: Pacu fish can grow to be quite large, reaching up to 30 inches in length, though the average adult measures 20-24 inches. This makes them suitable for larger home aquariums or outdoor ponds.
  • Color: Depending on the species, Pacu fish can showcase colors ranging from silver with dark bands (Black Pacu) to a more solid reddish hue (Red-Bellied Pacu).
  • Life span: With proper care and attention, these hardy fish can live for 15-20 years.
  • Teeth: Perhaps Pacu fish’s most distinctive feature, their teeth resemble human molars. This adaptation allows them to efficiently crush seeds, fruits, and nuts that make up a significant portion of their diet.

When identifying your Pacu fish, pay close attention to features such as:

  • Species (Red-Bellied or Black Pacu)
  • Size (average adult length between 20-24 inches)
  • Color (silver with dark bands or reddish hue)
  • Teeth (resembling human molars)

Having a clear understanding of the specific Pacu fish species in your care is integral for ensuring a healthy, happy aquatic pet.

Pacu Fish Supplies

Caring for your Pacu fish begins with setting up their home. Having the right supplies is essential to creating a comfortable environment for your fish. Here’s a list of supplies you’ll need to give your Pacu fish the best possible care:

  • Tank: Pacu fish need a large tank, as they grow quickly and can reach sizes of up to 30 inches. Start with at least a 150-gallon tank, upgrading to a bigger tank as your fish grows.
  • Filtration System: A proper filtration system is vital for maintaining water quality. Choose a powerful external canister filter or a powerful hang-on-back filter.
  • Heater: Pacu fish thrive in warm water, so you’ll need a reliable heater. Maintain a temperature between 76-82°F (24-28°C).
  • Thermometer: Monitor your tank’s temperature accurately with a digital thermometer.
  • Water test kit: Regularly testing your water ensures that it remains safe for your Pacu fish to live in. Test for ammonia, nitrites, nitrates, and pH levels.
Supply Purpose Recommended Product
Tank Spacious environment for your Pacu 150-gallon (minimum) aquarium
Filtration System Maintain water quality External canister filter or powerful hang-on-back filter
Heater Maintain optimal water temperature Submersible, adjustable aquarium heater
Thermometer Monitor water temperature Digital thermometer
Water test kit Test water quality Aquarium test kit (for ammonia, nitrites, nitrates, and pH levels)

Of course, you can also add decorations, hiding places, and plants to make your Pacu’s tank more stimulating. Just be sure to choose larger, sturdier decorations and plants as Pacu can be quite strong and may damage fragile items. Once you have gathered all the necessary supplies, you can move on to setting up your Pacu fish’s tank.

Pacu Fish Tank Setup

Setting up a suitable environment for your Pacu fish is essential for their well-being. As a beginner, it’s important to provide your Pacu with a comfortable and spacious tank, as Pacu fish can grow up to three feet long.

  • Tank Size: For juveniles, a 75-gallon tank is the recommended minimum, but keep in mind that as your Pacu grows, the tank size should also grow accordingly. A fully-grown Pacu requires a tank of at least 250 gallons. To ensure the fish have adequate space, consider upgrading the tank as they mature or provide outdoor swimming areas in warmer weather.
  • Substrate: A sandy or fine-grained bottom is ideal for Pacu fish. This simulates their natural habitat, enabling them to feel more at home in your tank. Avoid using sharp gravel or stones, as they may unintentionally injure the fish.
  • Decorations: Adding plenty of plants, driftwood, and hiding spots is essential in replicating the natural habitat of the Pacu fish. Keep in mind that Pacu fish are known to nibble on plants, so choose robust and durable ones, such as Java fern or Anubias.
  • Filtration and Aeration: Pacu fish produce a lot of waste, so efficient filtration is a must. Invest in a high-quality external canister filter to keep the water clean and clear. Additionally, ensure that adequate aeration is provided through air stones or a bubbler to maintain proper oxygen levels.
  • Heater: Pacu fish thrive in warm water, so maintaining a stable temperature of 76–82°F (24–28°C) is crucial. Install a reliable heater and a thermometer to monitor the water temperature.

Once you’ve successfully set up the tank, allow the tank to cycle for at least two to three weeks before introducing your Pacu fish. This ensures a stable biological balance, making the environment safer and healthier for your new fishy friend.

Pacu Fish Water Requirements

Pacu fish originate from the Amazon River basin, so it is important to recreate their natural habitat as closely as possible in your home aquarium. To ensure their well-being and happiness, providing them with the right water parameters is crucial.

  • Temperature: Pacu fish thrive in warmer water temperatures ranging from 76°F to 82°F (24°C to 28°C). It is advisable to use an aquarium heater and thermometer to ensure a stable temperature within this range.
  • pH level: A slightly acidic to neutral pH level, between 6.0 and 7.5, is best for Pacu fish. You can use a reliable water testing kit to monitor the pH level in your tank.
  • Water hardness: Pacu fish can adapt to a range of water hardness levels. However, they appreciate soft to moderately hard water, with a hardness of 4 to 18 dGH.

Regular water maintenance is necessary for the health of your Pacu fish. Perform 25% to 30% water changes weekly to keep the water fresh and toxin-free. Additionally, invest in a good quality aquarium filter to keep the water clean and clear. Pacu fish produce a significant amount of waste, so a powerful filter is essential.

Lastly, it is important to let the tank cycle before introducing your Pacu fish to their new home. This process establishes the necessary beneficial bacteria in the aquarium and helps stabilize the water parameters. A properly cycled tank ensures a healthy environment for your fish right from the start.

Pacu Fish Diet and Feeding

Pacu fish are omnivorous creatures, which means their diet consists of both plant-based and meat-based food items. Their natural feeding habits would include eating fruits, seeds, nuts, insects, and occasionally other fish.

Their strong teeth and powerful jaws are well suited to crushing and grinding the food they eat. Here’s what you should feed your Pacu fish in captivity:

  • Plant-based food: A major portion of your Pacu’s diet should be plant-based. Feed them a variety of vegetables like spinach, lettuce, peas, and zucchini.
  • Pellets: High-quality, sinking pellets are a suitable food source, as they provide balanced nutrition. Pacu fish need more than regular fish pellets, so opt for the larger ones specifically made for Pacu.
  • Live or frozen food: In addition to plant-based foods and pellets, you can provide live or frozen foods such as bloodworms, brine shrimp, and chopped earthworms. However, avoid overfeeding live food as it may cause health issues in the long run.

When feeding your Pacu fish, keep in mind that they can eat a lot, and overfeeding can lead to obesity and health issues. It’s best to adhere to the following feeding schedule:

  • Juvenile Pacu fish: Feed them two to three times per day, taking care not to overfeed them.
  • Adult Pacu fish: Feeding once or twice a day is sufficient, providing a good balance between plant-based and meat-based foods.

Make sure your Pacu has access to a constant supply of clean water, as this is crucial to their digestive health. Regularly removing uneaten food from the tank will help maintain water quality and prevent diseases. By ensuring a healthy and varied diet, you are contributing to the overall well-being of your Pacu fish.

Pacu Fish Care Schedule

Caring for your pacu fish involves several regular tasks to ensure they remain healthy and their environment is maintained properly. In this section, we will outline the care schedule you should follow for your pacu fish.


  • Monitor water temperature and ensure it stays within the 76-82°F (24-28°C) range. Adjust the heater as necessary.
  • Check the water’s pH level. Pacu fish thrive in water with a pH level between 6.5 and 7.5.
  • Observe your fish for any signs of illness or stress. Watch their behavior, respiration, and physical appearance.


  • Test water parameters like ammonia, nitrite, and nitrate levels using a test kit. Ensure they are within safe limits.
  • Replace 10-20% of the water with fresh, dechlorinated water to maintain water quality. Performing regular water changes can help prevent the buildup of harmful chemicals.
  • Clean the aquarium glass using a magnet cleaner or algae scrubber. This ensures that you can easily observe your fish without any obstructions.


  • Inspect all equipment, such as the filter, heater, and lighting, to ensure they are functioning properly. Clean filters and replace filter media as needed.
  • Prune and trim live plants to maintain the aesthetics of your aquarium and ensure they do not overgrow.
  • Vacuum the substrate using a gravel siphon to remove debris, such as uneaten food and fish waste.

By following this care schedule, you will provide your pacu fish with a clean and stable environment, reducing stress and promoting their overall health. Always remember to closely observe your fish and adjust their care routine as needed to address any potential issues. By being proactive in your pacu fish care, you will ensure a long, healthy, and happy life for your aquatic pets.

Pacu Fish Health Problems

Taking care of your Pacu fish should always include understanding the possible health issues they may encounter. These troublesome issues can be classified into infections, diseases, and parasites that might make your fish unhealthy.

  • Ichthyophthirius Multifiliis: Commonly known as Ich or White Spot Disease, this is a parasitic infection causing white spots to appear on the fish’s body. To combat this issue, raise the tank temperature to 86°F (30°C) for a few days and remove any infected fish to be treated separately.
  • Fin Rot: Recognizable by frayed or torn fins, fin rot is caused by bacterial or fungal infections. To treat it, improve the water quality and use a commercial remedy specifically made for fin rot.
  • Popeye Disease: An inflammation of the eye, this bacterial infection makes the fish’s eyes appear swollen. It’s crucial to maintain a clean tank and provide a balanced diet to prevent this issue.
  • Dropsy: A serious condition that can lead to the fish’s death, Dropsy causes internal organs to swell, resulting in visible bloating. Early treatment is essential, which involves isolating affected fish and administering antibiotics.
  • Swim Bladder Disease: This occurs when the fish has trouble with buoyancy, making it unable to swim properly. To treat it, feed your Pacu peas so as to flush out their digestive systems and improve water quality.

Always monitor the behavior of your Pacu fish and their tank mates to catch health problems early on. If you notice any irregularities, consult a professional and adopt a proper treatment regime to ensure your Pacu fish live a long, healthy life.

Pacu Fish Tank Mates

Choosing the right tank mates for your Pacu fish is crucial in order to maintain a peaceful and harmonious aquarium environment. Pacu fish can grow to be quite large, so it is essential to select tank mates that will be able to coexist peacefully with your Pacu without fighting for space, food, or territory.

Some preferred tank mates for your Pacu include:

  • Oscar fish: These South American natives are naturally compatible with Pacu fish due to their similar size and temperaments. Oscars are generally peaceful and will coexist with Pacu without any issues.
  • Plecostomus: This large, peaceful algae eater makes an excellent tank mate for Pacus due to their non-aggressive nature. They can grow up to 2 feet, which makes them a suitable companion for the large Pacu fish.
  • Giant Gourami: This large, highly adaptable fish is a great tank mate for Pacu. Reaching up to 28 inches in length, they are not aggressive and will not be intimidated by the Pacu’s size.
  • Large Catfish species: Many large catfish species, such as Synodontis Catfish, can live harmoniously with Pacu fish without posing a threat to each other.

However, it is crucial to avoid certain tank mates, including:

  • Small or slow-moving fish: Pacu fish might mistake these for food, which could lead to losses of smaller fish in your tank. Ensure the tank mates are large enough so that they don’t appear as prey to your Pacu.
  • Aggressive, territorial fish: Tank mates with such traits might create constant tension and stress among other fish in your tank, including your Pacu.

In conclusion, when selecting tank mates for your Pacu, consider their size, temperament, and compatibility with others to make sure everyone lives peacefully in your fish tank.

Pacu Fish Breeding

When it comes to Pacu fish breeding, it’s essential to know that breeding them in a home aquarium can be quite challenging. Pacu fish are generally bred in large ponds or commercial setups, mainly due to their size and specific requirements.

To begin the breeding process, you’ll need to set up a separate breeding tank with a minimum size of 1000 gallons as Pacu fish can grow quite large. Additionally, make sure that the water conditions are optimal for breeding, with a temperature of around 78-82°F and a pH level of 6.5-7.5.

  • Sexing Pacu fish: Determining the sex of Pacu fish can be difficult, especially during their juvenile stage. As they mature, the females develop rounder, fuller bodies, while the males have a hooked anal fin, known as a gonopodium.
  • Spawning behavior: Pacu pairs exhibit specific spawning behaviors, such as the male nudging the female’s belly or both fish swimming in tight circles. Observing these behaviors can indicate that your Pacu fish are ready to breed.

One essential element for successful Pacu fish breeding is providing a suitable spawning site. Pacu fish are egg layers and prefer using flat surfaces, such as large rocks or pieces of slate, to lay their eggs. Clean and smooth these surfaces to be placed in the breeding tank.

Finally, make sure you provide a proper diet for your breeding Pacu fish to improve their overall health and, consequently, their breeding chances. Offering a mix of high-quality pellets or flakes, fresh vegetables, and occasional live or frozen foods will give them the required nutrients.

Breeding Pacu fish in a home aquarium is a complex and demanding process. However, if you’re determined to take on this challenge, the key lies in providing optimal conditions, including a suitable breeding tank, proper diet, and a safe spawning environment.


Pacu fish care requires in-depth understanding of their needs, including selecting the appropriate tank mates and addressing challenges posed by their breeding. With the right amount of dedication and knowledge, you can nurture these fascinating fish successfully. Please feel free to leave a comment, if you have any further questions or tips for fellow aquarists.

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