Pacu Care Guide
The Pacu (Piaractus and Colossoma species) is one of the largest freshwater fish occasionally kept by UK aquarists. Often mistaken for piranhas due to their similar appearance, pacu are actually primarily herbivorous fish known for their impressive size, intelligence, and powerful jaws.
In this guide, you'll learn everything you need to know about Pacu care, including tank size, water conditions, compatibility, feeding, and typical UK prices - plus how to buy or sell them locally.
Quick facts about Pacu
Pacu are native to the rivers and floodplains of South America, including the Amazon Basin. Juveniles are often sold at just a few centimetres in length, but many species grow to enormous sizes and quickly outgrow standard aquariums.
They are highly intelligent fish that can recognise their owners and display surprisingly interactive behaviour.
Piaractus brachypomus, Colossoma macropomum, and related species
60-100 cm+ depending on species
South America (Amazon and Orinoco Basins)
1,500L+ (400gal+) for adults
15-25+ years
Generally peaceful, powerful, active
24-30°C
Omnivore with a strong preference for plant matter
6.0-7.5
£10-£50 for juveniles, significantly more for large specimens
How Many Pacu Should You Keep?
Pacu are usually kept singly due to their eventual size requirements.
- Single specimens are most common in aquariums
- Multiple pacu require extremely large systems
- Public aquariums and specialist fishkeepers are often best equipped for groups
Keeping too many fish can lead to:
- Overcrowding
- Water quality problems
- Competition for space and food
Their adult size makes long-term planning essential.
Ideal Tank Conditions for Pacu
Providing the right environment is critical for this giant species.
- Tank Setup: Extremely large aquarium or indoor pond
- Substrate: Sand, gravel, or bare-bottom systems
- Plants & Decor: Minimal delicate décor, robust wood and large open swimming areas
- Water Conditions: Clean, warm freshwater with stable parameters
- Filtration & Flow: Heavy-duty filtration capable of handling significant waste production
- Lighting: Moderate lighting
Pacu are powerful fish and can easily damage decorations, heaters, and poorly secured equipment.
Compatibility with Other Fish
Pacu are generally peaceful but their size creates compatibility challenges.
- Good Tankmates: large silver dollars, arowanas, giant gouramis, large catfish, datnoids, and other suitably sized species
- Avoid: small fish, delicate species, and anything that could fit into a pacu's mouth
Although not aggressive predators, very small fish may eventually be eaten accidentally.
Are Pacu Easy to Care For?
Pacu are relatively hardy but difficult to house properly.
They require:
- Extremely large aquariums
- Industrial-scale filtration
- Significant ongoing maintenance
- Careful long-term planning
Their husbandry requirements make them suitable only for experienced keepers with adequate facilities.
Pacu Price in the UK
In the UK, juvenile pacu typically cost between £10-£50.
Prices vary depending on:
- Species
- Size and age
- Availability
- Import costs
The initial purchase price is often insignificant compared to the long-term housing costs.
Where to Buy Pacu in the UK
Pacu are occasionally available through specialist tropical fish retailers and monster fish enthusiasts.
Before purchasing a pacu, consider:
- Its eventual adult size
- Future housing requirements
- Filtration and maintenance costs
- Rehoming options if necessary
TankMate UK helps connect fishkeepers who want to buy, sell, or responsibly rehome large fish locally.
Can You Sell Pacu?
Yes - pacu are frequently rehomed as they outgrow standard aquariums.
Selling or rehoming locally is often the best option because it:
- Minimises transport stress
- Allows buyers to assess the fish in person
- Helps find suitable large-scale setups
TankMate UK allows you to list large fish quickly and connect with experienced keepers.
Feeding Pacu
Pacu are omnivores but consume large amounts of plant matter.
Key Tips
- Feed quality large pellets as a staple
- Supplement with fruits such as melon, grapes, and banana
- Offer vegetables including peas, spinach, and courgette
- Provide occasional protein-rich foods such as prawns, mussels, or earthworms
A varied diet is important for healthy growth and long-term health.
Common Problems with Pacu
Stunted growth, often caused by:
- Tanks that are too small
- Poor water quality
- Inadequate nutrition
Obesity, linked to:
- Overfeeding high-protein foods
- Lack of swimming space
Rehoming difficulties, caused by:
- Underestimating adult size
- Insufficient long-term planning
Many pacu ultimately require facilities beyond what most home aquariums can provide.
Why Pacu Are So Popular
- Impressive giant freshwater fish
- Highly intelligent and interactive
- Generally peaceful temperament
- Unique appearance resembling a giant piranha
- Can become long-term aquarium pets
When kept correctly, pacu become remarkable aquarium residents that develop strong personalities and impressive presence.
Frequently Asked Questions
No. While they are related, pacu are primarily herbivorous and generally much less aggressive.
Depending on the species, adults can exceed 60 cm and may approach 1 metre in length.
Yes, provided tankmates are large enough and the aquarium is sufficiently spacious.
Adult pacu require aquariums of at least 1,500 litres, with many specimens needing considerably more space.
Looking to Buy or Sell Pacu Locally?
TankMate UK connects fishkeepers who want to buy, sell, or rehome fish safely within their local area.
Whether you're searching for a giant freshwater showpiece fish or looking to responsibly rehome one that has outgrown its aquarium, you can:
- Browse fish available near you
- List your own fish in minutes
- Avoid the risks of shipping
Explore local listings with TankMate UK and find the right fish for your setup.