Pro
Redtail Catfish
Phractocephalus hemioliopterus
Arapaima
Arapaima gigas
Reviewed for accuracy · Last updated Jan 3, 2026, 4:30 PM
Arapaima are massive, territorial, and carnivorous fish that require very large tanks and careful management for safety and health.
Key Information
Water Type
Freshwater
Temperament
Aggressive
Care Level
Pro
Minimum Tank Size
10567 gal (40000 L)
Maximum Size
102 in (260 cm)
Lifespan
15–25 years
Diet
Carnivore
Migration
Resident
Arapaima Behavior and Compatibility
Arapaima should be kept with very large, robust species. Avoid any fish small enough to be preyed upon. Provide partitions or separate tanks for juveniles. Monitor behavior to reduce territorial aggression. Ensure adequate space to prevent stress and injury. Feed all tank mates sufficiently to minimize competition. Use visual barriers for juvenile-adult separation. Observe for signs of bullying or stress. Provide environmental enrichment to reduce boredom. Regularly check water quality for optimal conditions.
Best Tank Mates for Arapaima
Arapaima Tank Setup and Care
Arapaima are giant freshwater fish that require ponds or public-aquarium-scale systems, not standard home aquariums. They need extensive open swimming space, powerful filtration, and secure lids, as they may jump.
Maintain temperatures between 24–30 °C, with a pH of 6.0–7.5, GH 2–10, and KH 2–8. This species is strictly freshwater and should be kept at SG 1.000–1.005.
Keep décor minimal, avoid small or delicate tank mates, and perform frequent water changes. A large, well-balanced diet is essential to support their rapid growth and long-term health.
Curiosities About the Arapaima
Air-Breathing Giant
Arapaima possess a specialized swim bladder that functions like a lung, allowing them to breathe atmospheric air and thrive in oxygen-poor waters.
Ancient Lineage
Arapaima are considered living relics, with a lineage tracing back millions of years and minimal evolutionary change compared to many modern fish.
Arapaima Diet and Feeding
Arapaima are carnivores, feeding primarily on fish and crustaceans. Offer live or frozen prey and high-protein pellets. Feed large meals 1-2 times per day depending on age. Include variety to ensure balanced nutrition. Juveniles require smaller, more frequent feedings. Avoid overfeeding to maintain water quality. Monitor feeding behavior to prevent aggression. Remove uneaten food promptly to reduce pollution. Provide vitamin supplements occasionally for growth. Adjust diet as the fish matures and body size increases.
More Interesting Facts About the Arapaima
Predator and Prey Balance
Conservation Through Management
Arapaima populations have recovered in some regions due to controlled fishing programs and community-based conservation initiatives.
Arapaima Breeding and Reproduction
Arapaima breeding is difficult in captivity and rarely achieved. Spawning occurs in shallow areas with submerged structures. Males guard the eggs and juveniles in the wild. Artificial breeding involves controlled water and temperature conditions. Egg collection may be necessary for captive propagation. Provide nutritious diet for breeding pairs. Monitor water quality carefully to prevent mortality. Fry require very small live foods initially. Gradually increase size of food as juveniles grow. Ensure tank space accommodates adult size and behavior.
Arapaima Water Parameters
75–86 °F (24–30 °C)
6.0–7.5
2–10 dGH
1.000–1.005 SG
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Frequent Questions About Arapaima
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What tank size is required to keep Arapaima in captivity?
Arapaima require extremely large enclosures, with private aquariums being unsuitable due to their potential size exceeding 3 meters. Proper care is only feasible in public aquariums or licensed ponds measuring several thousand gallons to support natural movement and water stability.
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How challenging is Arapaima care compared to other large fish?
Arapaima care is highly advanced because of their massive size, oxygen requirements, and legal restrictions in many regions. Maintaining water quality, temperature stability, and secure enclosures is critical for long-term health.
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What behavior patterns are typical of Arapaima?
Arapaima are generally calm but highly territorial predators that require significant space. They are solitary by nature and do not exhibit schooling behavior, even when young.
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What is the natural diet of Arapaima and how is it replicated in captivity?
Arapaima are carnivorous and feed primarily on fish, crustaceans, and occasionally small vertebrates. In managed environments, their diet consists of large prepared carnivore feeds and whole fish to meet protein demands.
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Can Arapaima live with other large fish species?
Arapaima may coexist with very large, robust species such as Redtail Catfish or Black Pacu in expansive exhibits. Compatibility depends on enclosure size and constant monitoring to prevent predation.
