Juvenile clownfish are asexual. As they grow, the two largest in a school will pair off, with the largest growing ovaries (sexually maturing into a female) and the second largest becoming a male. If the female dies, the male turns into a functional female & the next largest juvenile sexually matures into a male. If the male dies, the female stays the same, and the next largest juvenile sexually matures into a male.
Hope that helps.
Anthony
PS. Now aren't you glad you're not a clownfish?
