Pacu Fish Care: Complete Guide for Beginners

Pacu fish care refers to the practices you need to maintain to keep your pacu fish healthy and thriving. As a beginner, you’ll learn how to create the right tank environment, meet their dietary needs, and protect them from health issues. This guide covers everything from fish identification to breeding, presenting a step-by-step approach to care for these unique and sizable freshwater fish.

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Pacu Fish Species Profile and Identification

Pacu fish are a group of large freshwater fish related to piranhas. Unlike piranhas, pacu fish have square, straight teeth, which look similar to human teeth. They use these teeth to crack nuts and eat plants. Pacu fish come from South America. They live in rivers and streams there.

People often confuse them with piranhas, but pacus are mostly peaceful and have different body shapes. You can identify a pacu by its size, color, and teeth. They grow large, sometimes reaching up to 3 feet in length. Their bodies are usually silver or gray. Some have spots or markings.

When you look at their teeth, you’ll see they are made for grinding, not tearing like those of a piranha. Knowing these features will help you spot a pacu fish.


When you keep a pacu fish, you need various items. These supplies help create a safe and comfy home for your fish.

You will need a large aquarium since pacu fish grow big. A sturdy stand holds the tank securely. Also, you need a filter to keep the water clean. A water heater is essential to maintain the right temperature. For the health of your pacu, a water testing kit checks for harmful chemicals.

Lighting is also necessary, especially if you have live plants inside your aquarium. Don’t forget an aquarium vacuum to clean the substrate. Use it when doing regular water changes.

You’ll need fish food designed for pacu’s diet. Collecting these supplies before your pacu comes home is smart.

Tank Setup

Setting up a tank for pacu fish takes careful planning. These fish grow large, so they need lots of space. Start with a tank that holds at least 120 gallons of water. This size allows the pacu room to move. Choose a strong filter to keep the water clean, as pacu produce a lot of waste. The tank should also have a heater to maintain a steady water temperature between 75°F and 82°F.

Add a mix of rocks, plants, and hiding places to mimic the pacu’s natural home. Avoid sharp decorations that may hurt the fish. Place the tank in a spot away from direct sunlight. This prevents unwanted algae growth. Make sure the tank’s lid is secure. Pacu are powerful and may jump out of the tank.

black pacu fish

Water Requirements

Pacu fish need lots of room to move in their tank. Your tank water must be clean and at the right temperature, pH level, and hardness for them to be healthy. The water temperature should be between 76°F and 82°F. A heater will help you keep the water warm enough.

The pH level is a number that tells you how acidic or basic the water is. For pacu fish, it should be between 6.5 and 7.5. You should also check how hard or soft your water is. Pacu fish need a hardness level of 2-15 dGH.

It’s important to change some of the water often, usually 20-25% every couple of weeks. This keeps the water good for the pacu fish to live in. Make sure to dechlorinate new water before adding it to the tank. Chlorine can hurt pacu fish.

You’ll need a filter to keep the water clean between changes. A strong filter works best because pacu fish can be messy. Check the water with a testing kit every week to make sure everything is still okay. If you see the water getting dirty or the levels changing too much, you may need to clean the tank or change the water more often.

Diet and Feeding

Pacu fish are unique in their eating habits. Like humans, they are omnivores. This means they eat both plants and meat. However, pacus prefer a plant-based diet. You should feed them a variety of foods to keep them healthy. These foods include:

  • High-quality pellet food made for herbivorous fish
  • Fresh fruits like apples and grapes, cut into small pieces
  • Vegetables like lettuce and zucchini, also in small pieces
  • Occasional protein sources like worms or small shrimp

Feeding your pacu fish the right amount is important. They tend to overeat if given the chance. Give them food once or twice a day. Only offer as much as they can eat in a few minutes. Over time, you’ll learn how much your pacu needs. This careful feeding helps prevent water pollution and health problems.

Care Schedule

Taking care of your pacu fish means creating a routine. This helps them stay healthy. Follow a schedule like the one below:

  • Daily
    • Feed your pacu fish with the right amount of food.
    • Check the water temperature and quality.
    • Look at your fish for any signs of stress or illness.
  • Weekly
    • Change 20-30% of the water in the tank.
    • Clean the tank’s sides by wiping away algae.
    • Test the water’s pH, ammonium, nitrate, and nitrite levels.
  • Monthly
    • Replace or clean filters to keep water clean.
    • Inspect all tank equipment to make sure it’s working.
    • Trim plants and remove any debris from the tank.
  • Yearly
    • Do a full check on all the equipment.
    • Review your pacu’s diet and make changes if needed.
    • Plan a vet check-up for a health assessment.

Remember, sticking to a schedule keeps your fish in the best shape.

Health Problems

Pacu fish can get sick just like any other pet. Some common health problems affect these fish. You need to know about these issues to keep your pacu healthy. Infections are a top concern. Bacteria, fungi, and parasites can attack your fish. Your pacu might get icky spots or wounds, and its behavior can change.

Poor water conditions often lead to these infections. Pacu fish can also get stressed. This happens when they’re not happy with their home. Stress can weaken their immune system, making them more likely to get sick. Being crowded with too many other fish is a common stress cause. Your fish might even hurt itself by banging against the tank if it’s not big enough.

Another issue is diet-related problems. If your pacu doesn’t get the right food, it can suffer from nutritional deficiencies. This can lead to unhealthy fish with weak bones or poor growth. Always watch your pacu for signs of sickness, such as changes in how it eats or swims.

Keeping the tank clean and feeding your pacu the right foods are great ways to prevent health problems. If your pacu does get sick, a vet who knows about fish can offer treatment and advice.

red bellied pacu fish

Tank Mates

Choosing the right tank mates for your pacu fish matters a lot. Pacu fish can grow very large. They need friends that can handle their size. Also, they swim fast and might scare smaller fish. Here’s a list of tank mates that get along with pacu fish:

  • Other pacu fish: They like being with their own kind.
  • Large catfish species: These are tough and can share space with pacus.
  • Cichlids (larger types): Big cichlids won’t get bullied by pacus.
  • Plecostomus: This algae eater can manage with pacus around.
  • Oscars: Another larger fish that can stand up to pacus.

Make sure your tank is big enough for these fish and the pacu. Please don’t mix them with small or timid fish. It could lead to trouble. Always watch how they act together when you first add new mates. This helps you see if they fit well in the tank.


Breeding pacu fish is a complex task. These fish spawn, which means they release eggs into the water to be fertilized. For success, you need a large tank because adult pacus can grow very big. You also need a male and a female fish. It’s tough to tell them apart, but males often have larger dorsal fins.

The water in the tank should be warm and have a low current to match their natural environment. When ready to breed, the female lays eggs. Then the male fertilizes them. The parents don’t usually care for the young. As an owner, you will need to protect the babies and feed them suitable food.

Keep in mind, that breeding pacus is often best left to experts or done in large outdoor ponds.

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