Lijiang Piranha

The Lijiang piranha (Megapiranha altus) is a large freshwater fish indigenous to the Hunan, Guanxi, and Jiangxi provinces of China. Lijiang piranha may exceed 450 kilograms (990 lb) in weight, which would make them the largest of the Perciformes.

However, Lijiang piranha frequent depths near the bottom of the mesopelagic zone and few bones have ever been discovered, leading them to be written off as cryptids.

Males are slightly larger than females, with several additional rows of jagged teeth. Males are on average about 20% larger than females.The Lijiang piranha have a lifespan of 50 years. Due to their rugged physique, the fish is highly resistant to habitat degradation as it can always swim to the bathypelagic zone for long periods of time (if applicable).

As an apex predator, the Lijiang piranha has few natural predators, of which only colossal squid and sperm whales are of any threat. Lijiang piranha eat almost anything they can catch, Only a few wily fishermen have been able to ever catch them but choose to keep their methods a secret, so as to preserve the fishes slow-breeding population. Local fishermen have tried in vain to catch the fish, but the fish's severe weight coupled with its sharp teeth, snap most test lines with little resistance at all. On hardier steel-spun lines, the fish's teeth will snap off, allowing the fish to escape capture.

Lijiang piranha lay hundreds of eggs several times a year during spring, and it is not uncommon for competitors to fight over a single female. Battles include biting at the others tail or fins, so as to incapacitate them and leave competitors to die if the losing fish doesn't disengage, suggesting a cruel, malicious intellect.

The young are often preyed upon by opportunistic predators of the deep, which are most often fish such as octopi, squid, and sperm whale. This accounts for their high mortality rate of 85%+ in their first two years. They swim close to their mothers until they are weaned at 22 months before the young swim closer to the surface to forage for smaller prey. Their sharp teeth help them avoid capture by chewing through drag-catch nets. They reach sexual maturity in 8 to 10 years, and a few of them will be maimed in mating rights.

As a side effect of the Lijiang piranha's large size, only the most successful fish are able to eat enough to avoid a slow starvation, being that much of the prey that the fish eats is far too small to keep up its metabolism. The weakened fish will often try to fish for bigger game in deeper water in the later years of their life, which often ends in them being devoured by their larger predators.

Trivia
The fish is sometimes erroneously referred to as a tuna. Aside from this being a reference to Team Four Star's episode featuring the fish, tuna are a saltwater fish without dentation.