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Why can fish change gender?
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A sex change phenomenon in fish suggests there is something in the water. A new study published in Ecotoxicology and Environmental Safety finds that male fish are turning into females – a phenomenon known as intersex – due to chemical pollution, specifically estrogenic endocrine disrupting chemicals or EEDCs.
Clownfish, wrasses, moray eels, gobies and other fish species are known to change sex, including reproductive functions. A school of clownfish is always built into a hierarchy with a female fish at the top.
Can a fish be male and female?
However, in a few vertebrates like fishes (and in plants and many invertebrate animals), a condition called hermaphroditism is common. A hermaphrodite is an organism that has both male and female reproductive organs and can perform both the male and female parts of reproduction.
How do fish become female?
Why can fish change gender? – Related Questions
Can male fish change gender?
Researchers have identified more than 500 fish species that regularly change sex as adults. Clown fish begin life as males, then change into females, and kobudai do the opposite. Some species, including gobies, can change sex back and forth. The transformation may be triggered by age, size, or social status.
Nearly all fish reproduce sexually, and most species have separate sexes. Those without separate sexes avoid self-fertilization by producing sperm and eggs at different times. Each fish typically produces a large number of gametes. In most fish species, fertilization takes place externally.
How did fish get pregnant?
In most cases, the females release eggs into the water and they are immediately fertilized by sperm from the male. In the wild, fish can easily reproduce when they sexually mature.
How do fish get each other pregnant?
The females of these species lay hundreds of eggs, usually in prepared nests on the floor, wall, or water surface. If there is a male in the same tank, he may fertilize the eggs after they are laid or by mating with the female beforehand, depending on the species. The eggs will eventually hatch into live fish.
Do female fishes have periods?
Fish do not have periods. They have internal sexual organs and ovaries that produce unfertilized eggs once a year. When the eggs have matured, the female will eject them into the water for external fertilization by the male. This process, called spawning, makes a menstrual cycle in fish unnecessary.
Can female fish reproduce asexually?
Despite odds, fish species that bypasses sexual reproduction is thriving. An international team of scientists has sequenced the genome of the Amazon molly, a fish that reproduces asexually. The researchers expected that the asexual organism would be at a genetic disadvantage, but the Amazon molly is thriving.
Can fish get pregnant without mating?
“What the DNA fingerprints told us was altogether more surprising: female sawfish are sometimes reproducing without even mating.”
In a study published in the Royal Society Open Science journal, a team details the case of female cichlid hybrid fish, a freshwater fish often kept in aquariums. The team noticed that the fish were able to impregnate themselves, producing healthy offspring who behaved — and reproduced — totally normally.
Can a fish self breed?
A species of freshwater fish can impregnate itself — by growing male sex organs and then mixing sperm and eggs in its own mouth, scientists said.
Do fish have balls?
Most male fish have two testes of similar size. In the case of sharks, the testes on the right side is usually larger.
Do fishes sleep?
While fish do not sleep in the same way that land mammals sleep, most fish do rest. Research shows that fish may reduce their activity and metabolism while remaining alert to danger. Some fish float in place, some wedge themselves into a secure spot in the mud or coral, and some even locate a suitable nest.
Can fish be hybrids?
Most hybrid fish are sterile so they aren’t distinct or new species, merely a combination of the two parental species, usually created by humans. In relatively rare cases, fish hybridization occurs naturally, but this isn’t necessarily a good thing.
Is it OK to inbred fish?
Although inbreeding, especially in the extreme form of self-fertilization, is ordinarily regarded as detrimental because it leads to expression of deleterious recessive alleles, self-fertilization does provide the benefit of “fertilization assurance” (reproductive assurance) at each generation.
Can 2 different fish species breed?
Fish will mate with a species outside their own if the male’s colouring is attractive enough or if the female can’t see him properly, according to new research. Such ‘mistakes’ in mate choice can lead to the evolution of new species, an international team of scientists found.
Make sure you only breed fish of the same species. While it may be possible for two different species to reproduce, there’s a good chance that the resulting hybrid will be feeble, deformed, or sterile. Pass over fish that appear sick, injured, or deformed. They’re less likely to produce healthy offspring.