How Fast Can an Alligator Gar Grow? A Real Growth Experiment Six months ago, I started a real-life aquarium experiment to test the growth speed of one of the most controversial invasive fish species - the alligator gar. Starting at just 10 cm long, this fish was given unlimited food in a controlled environment to observe how fast it could grow with no shortages. The results were shocking. Within a single week, it grew 3 cm. In less than one month, it passed 30 cm, outperforming nearly every orna