Do catfish experience a menstrual cycle?

No, they don't. Only primates experience an actual menstrual cycle. Other mammals experience an Estrus cycle which is the same as a menstrual cycle except that the blood is reabsorbed back into the body rather than being released. Mammals are the ONLY kind of animal that experience either cycle.

Nope. Only mammals have menstrual cycles.

giving the complete absence of an uterus in catfish (they lay eggs and do not give birth do live young) I will confidently answer this question with no.

I'm from down South and I've heard that before while I was living there but , I think it's just a myth...

Why in all that is holy would you even need to know the answer to this question.

not to the best of my knowledge. Few animals do.

I think I can safely say "Now I've heard it all."

No - only mammals do.