I. pygmaeus weighs 0.00033 g upon hatching and increases in weight to 0.175 g as it reaches maturity in 50 days (1260 degree days). It inhabits waters at a temperature of 25.2 °C. Growth rate has been calculated as 12.55 and physiological growth rate as 0.498. I. pygmaeus grows to 20 mm in mantle length. Learn more about Two-Tone Pygmy Squid