Final answer:
The giant Mekong type of barbeled fish, notable for its large size and significant weight, is the Catfish. This is an example of the variability in fish size, with some species like the whale shark and ocean sunfish being the largest and heaviest in their categories respectively.
Step-by-step explanation:
The giant Mekong type of barbeled fish known for its size and weight is the Catfish. Fish can vary greatly in size, with some species being known for their impressively large dimensions.
For instance, the whale shark is the largest fish, reaching lengths of 65 feet and weights of 75,000 pounds, while the ocean sunfish is noted for being the most massive bony fish, capable of growing up to 11 feet long and weighing as much as 5,070 pounds. However, the giant Mekong Catfish stands out for its notable size among freshwater fish, having the ability to reach significant weights indicative of its robust growth.
One should note that the whales mentioned for comparison are not fish, but mammals, and thus belong to a different category of aquatic animals.