Here is a mating pair of hamlets (Hypoplectrus spp.), the Caribbean fish who take turns being male and female, alternately producing and fertilizing their eggs. Hamlets are known as simultaneous (or synchronous) hermaphrodites. During a single mating session, a pair of hamlets will alternate male and female roles up to a dozen times! This behavior is known as "egg trading." In other breaking news from the world of fish, scientists in Australia have recently discovered that immature female green swordtails can accelerate their sexual maturation if they see a male with a particularly long tail.
Happy Valentine's Day!