Due to the secretive nature and good camouflage of the flounder, it rarely spotted by predators. Large fish, sharks, eels, humans, and marine mammals all prey on the flounder when it can be spotted.
Rather than laying her eggs onto an inanimate object or the leaf of a plant, female flounders release them into the water at the time time as the male flounders release their sperm (this form of fertilisation is known as spawning). Once the eggs have been fertilised, the flounder fry begin emerging from them in just a couple of weeks.