Cruel fish: The father is pregnant and then kills the child

The heartwarming story of the key fish of the lime fish came to an end after scientists discovered the fish that ate the baby during pregnancy.

Lime fish are marine animals that have long, slender bodies and swim vertically. They live in seagrass beds in warm waters. In fact, lime fish is a relative of seahorses.

After mating, the key fish turns hundreds of fertilized eggs into the male body. "Guys" will keep eggs in a small bag and nurture future offspring through special blood vessels until they develop into fry. For decades, the scientific community has considered the egg-carrying behavior of the father-of-the-lime fish is one of the most moving stories about fatherhood in biology.

A fish with a lime key.(Photo: liveaquaria.com).

National Geographic said, scientists from the University of Gothenberg, Sweden, tracked the big nose-keyed lime fish for many years. They detect some - even all - eggs disappear during the time the males carry them. Initially the expert team thought that fish fetuses took each other's nutrients.

"It is only later that we have speculated about the fish eating the fetus because of a lack of nutrients, " said Gry Sagebakken, a postdoctoral fellow in animal ecology at Gothenbert University.

To investigate this mystery, the team pumped traces of nutrients into the eggs of the fish eggs before the females transferred them to the "husband" body. They found that the markers appeared inside fathers' bodies. It seems that the blood vessels in the male's egg bag have two tasks. They nourish eggs, but also suck nutrients from eggs to supply them with the body.

Sagebakken said that when male lizardfish do not have enough food to nourish all eggs, they are forced to sacrifice a few children to increase the chances of surviving the remaining eggs. She will continue to research to find out if male males have enough food to feed them. If the male lizardfish still eats their children when they have enough food, the scientists will know a fellow carnivorous animal.