Freshwater
Pacu
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Black‑Finned Pacu (Colossoma macropomum)
Pro
Pro
Description
Massive and misunderstood, the Black-Finned Pacu resembles its piranha cousin but follows a peaceful herbivorous lifestyle. Known for its crushing jaws and surprising intelligence, this Amazonian giant is not for beginner tanks—it’s a species better suited to public aquaria or expansive pond systems.
Difficulty Level
Expert Only
Region
Black‑Finned Pacu (Colossoma macropomum)
Core Details
Highlights
Care Level
/ 10
Grows over 30 inches and requires enormous tank space, impeccable filtration, and a specialized plant-based diet.
Environment Impact
/ 10
Often wild-caught or irresponsibly sold to hobbyists with undersized tanks. Overpopulation and poor release practices have made it invasive in several non-native ecosystems.
Origin
Native to the Amazon and Orinoco River basins, especially in slow-moving floodplains, flooded forests, and nutrient-rich blackwater channels.
Visual & Functional Appeal
Broad-bodied and imposing, with dark fins, silver-gray scales, and a powerful profile. Offers a prehistoric feel in large displays and serves as a focal species in megafish aquariums.
Purpose
Primarily aesthetic and educational. Adds impressive mass, draws attention in public or specialty tanks, and contributes to vegetative cycling through its constant grazing on fruits, nuts, and plants.
Importance
Vital for natural seed dispersal in the wild. In captivity, it demonstrates the responsibility and scale needed to care for true megafish. Highlights the need for ethical fishkeeping and species-appropriate enclosures.
Included Resources
Requires tanks over 500 gallons or more. Needs powerful filtration, strong current breaks, and ample swimming space. May benefit from UV sterilizers and large driftwood/logs. Water parameters: 75–82°F, pH 6.0–7.5.
Best Use Cases
Ideal for zoos, aquaculture centers, or massive private aquaria. Not suitable for home aquariums unless custom-built. Compatible with other large, peaceful species in massive systems.
Conservation Context
Heavily fished in the wild for meat. Aquaculture has reduced some pressure, but habitat degradation still threatens native populations. Also an invasive risk where released into non-native waterways.
Ideal Aquatic Animals
• Giant gouramis
• Arowanas (in enormous tanks only)
• Large peaceful catfish (e.g., Sorubim spp.)
• Silver dollars (in groups)
• Other pacu (space permitting)
Region (A)
• Latitude: -3.4653° S
• Longitude: -62.2159° W
(Middle Amazon Basin — near Tefé, Brazil)
Region (B)
• Latitude: 6.4238° N
• Longitude: -66.5897° W
(Orinoco River Basin — central Venezuela)
How Many Can I Keep?
Get smart stocking suggestions based on your tank size.
e.g. 75 gallons (280 L)
Black‑Finned Pacu (Colossoma macropomum)
Core Details
Highlights
Care Level
/ 10
Grows over 30 inches and requires enormous tank space, impeccable filtration, and a specialized plant-based diet.
Environment Impact
/ 10
Often wild-caught or irresponsibly sold to hobbyists with undersized tanks. Overpopulation and poor release practices have made it invasive in several non-native ecosystems.
Origin
Native to the Amazon and Orinoco River basins, especially in slow-moving floodplains, flooded forests, and nutrient-rich blackwater channels.
Visual & Functional Appeal
Broad-bodied and imposing, with dark fins, silver-gray scales, and a powerful profile. Offers a prehistoric feel in large displays and serves as a focal species in megafish aquariums.
Purpose
Primarily aesthetic and educational. Adds impressive mass, draws attention in public or specialty tanks, and contributes to vegetative cycling through its constant grazing on fruits, nuts, and plants.
Importance
Vital for natural seed dispersal in the wild. In captivity, it demonstrates the responsibility and scale needed to care for true megafish. Highlights the need for ethical fishkeeping and species-appropriate enclosures.
Included Resources
Requires tanks over 500 gallons or more. Needs powerful filtration, strong current breaks, and ample swimming space. May benefit from UV sterilizers and large driftwood/logs. Water parameters: 75–82°F, pH 6.0–7.5.
Best Use Cases
Ideal for zoos, aquaculture centers, or massive private aquaria. Not suitable for home aquariums unless custom-built. Compatible with other large, peaceful species in massive systems.
Conservation Context
Heavily fished in the wild for meat. Aquaculture has reduced some pressure, but habitat degradation still threatens native populations. Also an invasive risk where released into non-native waterways.
Ideal Aquatic Animals
• Giant gouramis
• Arowanas (in enormous tanks only)
• Large peaceful catfish (e.g., Sorubim spp.)
• Silver dollars (in groups)
• Other pacu (space permitting)
Region (A)
• Latitude: -3.4653° S
• Longitude: -62.2159° W
(Middle Amazon Basin — near Tefé, Brazil)
Region (B)
• Latitude: 6.4238° N
• Longitude: -66.5897° W
(Orinoco River Basin — central Venezuela)
How Many Can I Keep?
Get smart stocking suggestions based on your tank size.
e.g. 75 gallons (280 L)
Black‑Finned Pacu (Colossoma macropomum)
Core Details
Highlights
Care Level
/ 10
Grows over 30 inches and requires enormous tank space, impeccable filtration, and a specialized plant-based diet.
Environment Impact
/ 10
Often wild-caught or irresponsibly sold to hobbyists with undersized tanks. Overpopulation and poor release practices have made it invasive in several non-native ecosystems.
Origin
Native to the Amazon and Orinoco River basins, especially in slow-moving floodplains, flooded forests, and nutrient-rich blackwater channels.
Visual & Functional Appeal
Broad-bodied and imposing, with dark fins, silver-gray scales, and a powerful profile. Offers a prehistoric feel in large displays and serves as a focal species in megafish aquariums.
Purpose
Primarily aesthetic and educational. Adds impressive mass, draws attention in public or specialty tanks, and contributes to vegetative cycling through its constant grazing on fruits, nuts, and plants.
Importance
Vital for natural seed dispersal in the wild. In captivity, it demonstrates the responsibility and scale needed to care for true megafish. Highlights the need for ethical fishkeeping and species-appropriate enclosures.
Included Resources
Requires tanks over 500 gallons or more. Needs powerful filtration, strong current breaks, and ample swimming space. May benefit from UV sterilizers and large driftwood/logs. Water parameters: 75–82°F, pH 6.0–7.5.
Best Use Cases
Ideal for zoos, aquaculture centers, or massive private aquaria. Not suitable for home aquariums unless custom-built. Compatible with other large, peaceful species in massive systems.
Conservation Context
Heavily fished in the wild for meat. Aquaculture has reduced some pressure, but habitat degradation still threatens native populations. Also an invasive risk where released into non-native waterways.
Ideal Aquatic Animals
• Giant gouramis
• Arowanas (in enormous tanks only)
• Large peaceful catfish (e.g., Sorubim spp.)
• Silver dollars (in groups)
• Other pacu (space permitting)
Region (A)
• Latitude: -3.4653° S
• Longitude: -62.2159° W
(Middle Amazon Basin — near Tefé, Brazil)
Region (B)
• Latitude: 6.4238° N
• Longitude: -66.5897° W
(Orinoco River Basin — central Venezuela)
How Many Can I Keep?
Get smart stocking suggestions based on your tank size.
e.g. 75 gallons (280 L)
Black‑Finned Pacu (Colossoma macropomum)
Region
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