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Pacu Care Basics

Basic Information on Keeping a Pet Pacu in Your Aquarium

(The First Tank Guide)

Pacu Overview:

Pacu are members of the Serrasalminae sub-family of Characins. The Characins is the group of fish, primarily from South America and Africa, that is best known as the Tetras. The Serrasalminae sub-family of Tetras contains the Pacu and their close cousin, the Piranha. These fish are from South America and have many similarities in both appearance and behavior.

Pacu are generally very large fish, smaller species reaching around six inches (about fifteen centimeters) and larger species exceeding two feet (sixty centimeters), with record-setting fish over three feet (ninety-two centimeters) in length. These fish generally live for four to twenty years, depending on the species and the quality of care provided for them (larger varieties tend to live longer).

Pacu Equipment & Maintenance:

To keep a Pacu healthy remember to provide them with plenty of clean, warm water. Your Pacu's aquarium temperature should be about 79° Fahrenheit (about 26° Celsius), and ideally should remain between 76° and 82° F (24.5° and 28° C) so you need an aquarium heater and a thermometer. Keeping your Pacu too warm for long periods of time will result in Oxygen deprivation, which can cause nerve damage, heart damage, and can seriously hamper the immune system. Keeping them too cool or exposing them to sudden chill can also hamper their immune system. An impaired immune system makes them more susceptible to many diseases, from easily treatable Ick to more difficult diseases such as dropsy or mouthrot.

Keep your Pacu in a large fish tank, providing at least 2 gallons or aquarium volume per inch of mature fish length (about 8 liters for every 2.5cm), this provides sufficient space for your Pacu so he can remain healthy, and also allows the aquarium to help you keep healthy fish. I recommend a minimum of 30 gallons (about 114 liters) for any Pacu aquarium, though larger varieties or species, or multiple fish, will mandate a larger fish tank.

Perform your weekly 10-15% water changes so that your Pacu always has clean water and any waste that is not processed by the filter is removed. Your Pacu need a filter to keep the water in their fish tank from becoming toxic, and you need to keep the filter in good condition.

When selecting a filter, remember to make sure that the filter provides sufficient filtration for a fish tank with the large capacity that your Pacu require. Many people use two or more smaller filters to maintain a large fish tank, such as those required by Pacu. Using two smaller filters allows you to stagger your filter maintenance so that you are not changing all of your filter media at once and risking cycling your fish tank again. However, it is still important that your filters provide sufficient filtration for your total aquarium volume.

Pacu Food & Care:

Remember that your Pacu is omnivorous (eats anything), so provide him with a varied diet. Many high quality processed fish foods are available on the market today, and most frozen fish foods are also appropriate. In the wild, most Pacu eat primarily vegetable matter, only opportunistically taking bites of fishes' fins or scavenging on an old carcass, so you are best off to try to duplicate this in the aquarium environment.

As a supplement to your processed and frozen foods, offer the Pacu fresh green vegetables, such as sliced raw zucchini, spinach, and pieces of raw potato. There are also many processed plant-based foods that are excellent for your Pacu. Your fish should be able to consume all the food you offer within two minutes of feeding (the exception to this being fresh vegetables, which can be left for several hours before starting to decay). If there is food in the aquarium after this time has elapsed, it will contribute to poor water quality and make your Pacu more susceptible to disease.

Though Pacu will take live foods, feeding live goldfish is always a bad idea. Feeder goldfish are not a very nutritious food, and they are a good way to spread disease to your beloved Pacu.

You only need to feed your Pacu once a day. If you feed more than once a day you increase the waste your fish are producing and also increase the risk of overfeeding, so it becomes more important that you are performing your weekly 10-15% water changes and all necessary filter maintenance. Providing a proper diet increases your Pacu's life expectancy and bolsters their immune system.

Pacu, like the majority of fish, are aware that they are prey animals. In order to feel comfortable, they need to have lots of hiding places.

Pacu do not seem to be too particular about their cover, however, you do want to make sure that you do not use any sharp or rough decorations that your fish may get hurt on, in case your fish dart into them when startled.

Like most other fish, they are more comfortable and will come out more and be more active if you can provide them with 50-75% cover - this means you should make half to three fourths of your fish tank space hiding places. Remember that if you use live plants to decorate your Pacu tank, you will likely have fish grazing on the plants substantially and detracting from the appearance of the aquarium.

Providing sufficient cover reduces stress and therefore improves your Pacu's immune system, reducing chance of disease.

Pacu Companionship:

As juveniles, Pacu are schooling fish, and should be kept in groups. However, as they mature, many varieties of Pacu become more solitary and no longer need same-species companionship. Pacu can, like most fish, be kept with fish with similar care requirements and temperament. This generally means fish that are going to get large and that are neither too aggressive nor too timid, as the Pacu will occasionally nip fins.


Remember, Pacu are beautiful living creatures. It is the responsibility of the pet owner to care for their pet and provide a healthy environment. So give your Pacu space, clean, warm water, plenty of hiding places, and high-quality, highly varied foods and he should be a good companion for a long time.

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September 27, 2005
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March 2, 2011
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