HARLINGEN, Texas (ValleyCentral) — It is thought to occur only a handful of times each decade, and it is happening right now in the remote backwaters of southernmost Texas, as the state’s largest freshwater fish is spawning.

Recent rains have triggered an impressive gathering of Alligator gar in a secluded wetland in the lower Rio Grande Valley.

The water is so clear in this isolated realm that the lazily swimming gar appears to almost be in an aquarium-like setting.

They gather in large schools of a dozen or more with the massive torpedo-shaped five to six-foot females attracting numerous smaller suitors.

Conditions must be precise for successful spawning to occur in late spring and early summer with overbank flooding triggering the event.

Congregations gather and then disperse from deeper water; swimming into grassy shallows where females deposit their eggs over freshly inundated vegetation. Males then release clouds of milt to fertilize the eggs as they are released.

Only a few days are required for the eggs to hatch and the young grow rapidly, exceeding five inches after only a month and up to 30 inches in a year.

However, the rapid growth lasts only a few years, as a six to seven-foot alligator gar may be some 50 years old.

Periodically, gar rise to the surface and gulp for air. They have gills like other fish, but they also have a highly vascularized swim bladder lung that supplements gill respiration, which helps them survive in water where most fish would die of suffocation.

This remarkable gathering lasts only a few days during peak flooding and presents an incredible opportunity to observe one of the most fascinating fish in Texas.