The freshwater rivers of South America and Southeast Asia house some of the largest fish species on our planet. Among them, the arapaima stands out not only for its size but also for its gastronomic and scientific value.
The arapaima is considered a "living fossil" by scientists, not because it has been hunted for centuries but due to its remarkable characteristics. It holds the position as one of the largest freshwater fish, with some individuals surpassing the size of any other in this environment. The largest arapaima can grow up to 4.6 meters in length and weigh around 200 kilograms. To put this in perspective, another large fish, the beluga, reaches a maximum length of only 4.2 meters. Belonging to the tropical freshwater ray-finned fish category, the arapaima is considered a "living fossil" due to its morphological traits, reminiscent of organisms whose biological relatives went extinct millions of years ago. To put it into context, fish emerged approximately 135 million years ago, while dinosaurs vanished from the Earth's realm around 65 million years ago.
Predatory in nature, the giant arapaima consumes small fish and occasionally preys on birds or small animals found in the water. Interestingly, it hunts primarily on the water's surface. What makes the arapaima truly unique is its ability to breathe atmospheric air. Unlike most other fish, it possesses a specialized tissue filled with blood vessels that closely resembles mammalian lung tissue. This adaptation allows the arapaima to survive through droughts, when it may find itself in shallow water or even dry riverbeds.
The arapaima follows an intriguing reproductive process. Spawning occurs in April and May, where males excavate holes at the riverbed, and the females subsequently lay their eggs in them. Over the next 48 hours, the parents diligently guard the nest. The male, through the release of specific pheromones, keeps the fry in close proximity to the nest. Until the young offspring grow and develop into capable hunters, the male assumes responsibility for their nourishment. The fish's unique glands, situated above their eyes, secrete nutrients into the water, enabling the male to feed his young. The fry exhibit rapid growth, adding an average of 5 cm to their length each month after transitioning to adult food.
Nature often exhibits the predator-prey relationship, and the arapaima is no exception. However, for many years, this species has endured human predation as its main threat. People have been catching arapaima for its delectable meat since ancient times. Notably, arapaima meat is renowned for its delicious taste and virtually boneless composition. The industrialized catching of this freshwater predator commenced in the 19th century, resulting in a significant decline in its population. Consequently, numerous countries where this ancient predator resides have now prohibited its capture to safeguard its survival.