Arapaima: The Amazon’s Living Fossil and Giant Fish Story
Discover the story of Arapaima, the Amazon giant fish. From its habitat and diet to survival, breeding, and fun facts, meet this living fossil of rivers.
Arapaima (Arapaima gigas), Pirarucu, or in certain Indian languages "Bade Machhli", is a world-record freshwater fish. With its prehistoric background, enormous size, and air-breathing capacity, the Amazon giant is a living fossil, having walked the earth for more than 100 million years. It is a top carnivore and a natural wonder. This guide covers everything from Arapaima's habitat and species to its diet, breeding, survival, and aquarium care.
Native Habitat
Arapaima are native to the Amazon River Basin, with habitat in Brazil, Peru, Colombia, and Guyana. They live in slow-moving rivers, lakes, floodplains, and low-oxygen waters, taking shelter among dense plants. Seasonal flooding is essential for breeding, with nutrient-rich waters for eggs and fry.
Key points for best habitat:
Temperature: 25–32°C (77–90°F)
pH: 6.0–7.0
Water: Soft to moderately hard freshwater
Environment: Dense vegetation areas for hunting and cover
How Many Species Are There?
There are four known species or forms of Arapaima:
Arapaima gigas: Common in aquaculture, reaches 3 meters.
Arapaima leptosoma: Occurs in some Peruvian and Brazilian rivers, reaches 2.5 meters.
Arapaima mapae: Uncommon northern Amazon species, raches 2 meters.
Arapaima arapaima: Occurs native in Brazil, reaching a length of approximately 3 meters, sometimes mistaken as A. gigas.
Most aquarists keep A. gigas because it is available and its care needs are well documented.
Maximum Size
Length: Up to 3 meters (10 feet) in the wild
Weight: Up to 200 kg (440 lbs)
Rapid growth: Grows juveniles to 1 meter in 2–3 years
Adults mature more slowly once they have reached early size milestones
Optimal Water Temperature
Ideal: 25–32°C (77–90°F)
• Soft, lightly acidic water with low to moderate current preferred • Health requires stable water conditions • They tolerate oxygen-poor waters because of air-breathing capability
Food Habits & Diet Plan
Wild diet consists of:
Small fish
Crustaceans and shrimp
Insects
Every now and then small mammals or birds
Captive diet consists of:
High-protein pellets for large carnivorous fish
Frozen or live fish
Shrimp or other crustaceans
Frequency of feeding:
Juveniles: 2–3 times/day
Adults: Once/day
Male vs Female Difference
Size: Males slightly more substantial than females
Breeding role: males construct and defend nests; females oviposit and can depart
Coloration: males can exhibit more intense tail redness during breeding
Breeding
• Takes place in the Amazonian rainy season
• Males excavate shallow-water nests
• Eggs are buoyant and need parental care
• Male defends fry for weeks
Sexual maturity: 4–5 years
How They Survive Air-breathing: obligate air-breathers thrive in low-oxygen water
Armored scales: defend against predators
Jumping ability: able to jump out of water for food or refuge
Ambush predator: Stealth and speed aid in hunting
Distribution
Found in the Amazon River Basin: Brazil, Peru, Colombia, Guyana
Prefers flooded forests, lakes, and slow rivers Seasonal migration during rainy season for breeding
Dos and Don'ts
Dos: • Provide large swimming space
• Maintain stable water temperature
• Feed high-protein diet
• Monitor water quality regularly
Don'ts:
• Avoid overcrowding
• Avoid aggressive or small tankmates
• Don't keep juveniles in small aquariums for extended periods
• Avoid sudden changes in water conditions
Fun Facts
• Can breathe air and live in low-oxygen water
• Can jump up to 2 meters out of water
• Armored scales provide protection
• Juveniles school together, adults are solitary
• Referred to as living fossils, living for more than 100 million years
Faqs
1. Can Arapaima be kept in home aquariums?
Only juveniles can be kept in very large tanks. Adult Arapaima require thousands of liters of water, which makes them suitable only for public or commercial aquariums.
2. How fast do they grow?
Arapaima grow rapidly, reaching up to 1 meter in just 2–3 years, but their growth slows as they mature.
3. Are they endangered?
Yes, they are considered vulnerable due to overfishing, habitat destruction, and the harvesting of breeding adults.
4. What do they eat in captivity?
In aquariums, they eat high-protein pellets, frozen fish, shrimp, and sometimes live feed for stimulation.
5. How long do they live?
Arapaima can live up to 20 years in the wild, and slightly less in captivity if not given proper care.
