Do fishes pee? interesting facts
Have you ever heard the phrase to drink like a fish?
well unless you're an ocean dwelling species that probably means staying sober because freshwater fish don't drink saltwater fish near their hand they're constantly drinking but if some fish drink all the time and whether fish don't drink at all we're left with an obvious question do fish pee?
what you've never wondered that water is essential to life as we know it to keep their chemistry running smoothly living things need just the right amount of water in their bodies you'd think that fish haven't made when it comes to staying hydrated but it's not so easy fish gills let oxygen flow into their bodies but they're also letting water constantly escape the ocean water is saltier than the insides of fish so water wants to move from the inside out to balance that out that's a problem if you're a fish who wants to stay alive it's a process called osmosis and we can demonstrate that with these eggs and I've dissolved the shells away leaving a membrane that'll allow water to pass through one is covered in pure h2o and one goes into sugar syrup now the syrup contains lots of sugar molecules and not much water so water passes out of the egg to balance it out and the egg shrinks life is all about balance homeostasis now.
we keep the salts and dissolve chemicals in our blood balanced by flushing the extra out here our kidneys and by drinking fresh water when we're thirsty but ocean fish only have one option drink saltwater in order to get the h2o they need to stay alive and most of them do that a lot but they need to get rid of the salt without dehydrate which they do using special cells and the gills that pump out the extra ocean fish only make a tiny amount of your and what little pee they do make is almost a salty as the pool they're peeing it the freshwater fish have the opposite problem their insides are saltier than where they live so water is constantly leaking in through their skin and gills it's just like the naked egg we put in pure water the inside of the egg is saltier than the water around it so water flows in and the egg swells up the plus they get even more water from their food so even in their wet world they never have to take a drink freshwater fishes have to get rid of water constantly to keep their cells from bursting which means they pee a lot like they're pretty much peeing all the time if I peed as much as a freshwater fish I'd release 28 litres a day which is about 20 times more PE than I usually make for fish peeing in the yard is a big help to their neighbors fish pee is full of ammonia a nitrogen containing compound and phosphorus both nutrients that plants crave these also help feed algae and coral reefs like a liquid fertilizer that helps keep aquatic ecosystems healthy.
Fish are little swimming urinating nutrient recycling plants but some fish get crazy with this salt and water balancing act some are able to live in water so salty it's hard for them to even stay below the surface others like salmon can tweak their body chemistry to move between its salty and fresh water sharks and their relatives aren't especially weird when it comes to salt balance using a special enzyme they stuff urea another nitrogen containing compound into their tissues by loading their insides with another ion they keep water from wanting to rush out of their bodies it's also why their meat smells like pee more thankfully we don't do that I smell great but we do owe our ability to regulate water and salt to our fishy ancestors the scientists think that a healthy salt level for the bodies of most living animals is about the same concentration as the ancient oceans where life began you know you even have evidence of this in your body before we're born human embryos develop three different types of kidneys a to get absorbed and one eventually becomes the final pair the extra organs are an evolutionary leftover early kidneys that we also see in primitive fish who use it to balance their salty bodies it reminds me of the famous poem by IP freely tinkle tinkle little fish homeostasis is what you wish the oceans your toilet and even though you soil it you really have mastered your niche stay curious a big thank you to curiosity stream for supporting PBS Digital Studios the curiosity stream is a subscription streaming service that offers documentaries and nonfiction titles from a variety of filmmakers including curiosity stream originals for instance curiosity stream offers deep time history the three-part series chronicling how human history has been shaped by science even before we knew what science was from the surprising ways that humans first figured out how to harvest energy to how the Scientific Revolution ended up putting salt and pepper on your table you can learn more at curiosity stream dot-com slash smart and use the code smart during the signup process you
