Do fish pee?
@GardenGerty (169406)
United States
February 19, 2026 6:35pm CST
I googled this for a kiddo.
The textbook, in discussing the hydrosphere and biosphere talked about part of the water cycle being completed by animals peeing. It went on to say that instead of peeing, fish took care of their waste through the gills, flushing and filtering the "water".
I will give more of an answer later, but I am asking you, "In your opinion, do fish pee?"
My student also had an opinion.
13 people like this
12 responses
@DaddyEvil (174208)
• United States
20 Feb
Yes, they do. Some fish, like goldfish use their urine to drive other fish out of their territory. That's why you don't want to keep goldfish with other fish. Their pee poisons the water.
3 people like this
@GardenGerty (169406)
• United States
22 Feb
Well you have added to my knowledge today. I knew they peed and goldfish did a lot but I did not know they were toxic to other fish. Fish tank water makes good fertilizer.
2 people like this
@DaddyEvil (174208)
• United States
22 Feb
@GardenGerty Yes, it sure can. When new fish were brought in to Walmart, I had to make sure new fish weren't added to the goldfish tanks or we'd lose them all. I'm kinda glad Walmart quit selling fish. Some of the suppliers would purposely dump expensive fish into the goldfish tank.
@toniganzon (77064)
• Philippines
20 Feb
I have seen fish poop so I guess they pee too.
3 people like this
@GardenGerty (169406)
• United States
22 Feb
You are right. They do both in addition to filtering through their gills.
2 people like this
@celticeagle (189793)
• Boise, Idaho
20 Feb
How interesting. I never thought about but now I know.
2 people like this
@GardenGerty (169406)
• United States
22 Feb
Yes. I never thought about their gills also being a filter, but I always assumed they peed. that is why your aquarium gets so high in ammonia.
2 people like this
@GardenGerty (169406)
• United States
22 Feb
You get asked lots of questions when you work with kids.
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@BarBaraPrz (51811)
• St. Catharines, Ontario
20 Feb
Never thought about it. I do know they poop, though.
2 people like this
@GardenGerty (169406)
• United States
22 Feb
Yes, I was looking it up for a kid.
1 person likes this
@GardenGerty (169406)
• United States
22 Feb
It makes good soil enrichment if you water plants with it.
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@GardenGerty (169406)
• United States
22 Feb
What I looked up did not talk about the amounts or composition. I knew they produced a lot of ammonia in their waste. The reference said they have kidneys and do pee. The text book in class only said they cleared their waste through their gills but the young man I was working with said he was sure he had been peed on by a fish.
1 person likes this
@GardenGerty (169406)
• United States
22 Feb
That was a good explanation. I did look this up for a kid, because the text book did not say they peed.
2 people like this
@LindaOHio (222222)
• United States
20 Feb
They do it in their own way. As rebelann says, they have to get rid of waste.
2 people like this
@GardenGerty (169406)
• United States
22 Feb
Yes, all living things must get rid of waste. The article I looked at said yes, they do.
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