Do fish pee?

Written by on August 19, 2016 in Fish, Marine Life

The short answer is: yes. Fish have kidneys and they produce urine, which contains things like creatine, urea, ammonia, and nitrogenous waste.

The longer answer is: yes AND fish pee is important.

Nassau grouper over a reef. Photo credit: Craig Layman/North Carolina State University.

Nassau grouper over a reef. Photo credit: Craig Layman/North Carolina State University.

Fish pee is especially important to coral reefs. When fish urinate, they release phosphorus and ammonium, which are two key elements for coral reef growth and survival. A new study found that in coral reefs where fishing occurs, many key nutrients are missing because there are fewer big fish peeing on the reef. In areas with less fishing and more large, predator fish, nutrient levels were healthy.

“Part of the reason coral reefs work is because animals play a big role in moving nutrients around,” lead author Jacob Allgeier, a postdoctoral researcher at the University of Washington’s School of Aquatic and Fishery Sciences, explained in a news release.

“Fish hold a large proportion, if not most of the nutrients in a coral reef in their tissue, and they’re also in charge of recycling them. If you take the big fish out, you’re removing all of those nutrients from the ecosystem.”

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Copyright © 2016 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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