Catfish (Siluriformes) do not have menstrual periods. In fact, no fish species on earth does! ... And as catfish are depositing their unfertilized eggs into the water, there is really no need for a menstrual cycle that would have to control the female's hormones, uterus, or the internal release and navigation of the eggs.

Do fishes get their period?

Fish do not have periods. They have internal sexual organs and ovaries that produce unfertilized eggs once a year. When the eggs have matured, the female will eject them into the water for external fertilization by the male. This process, called spawning, makes a menstrual cycle in fish unnecessary.

Which animals get periods?

Beyond primates, it is known only in bats, the elephant shrew, and the spiny mouse. Females of other species of placental mammal undergo estrous cycles, in which the endometrium is completely reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle.