• Question: Do fish get thirsty?

    Asked by Tír Na nÓg to Ahmed, Francesca, George, James, Nitheen on 18 Nov 2014.
    • Photo: James Sullivan

      James Sullivan answered on 18 Nov 2014:

      OOo- nice question – and google tells me that freshwater fish dont drink water – because their inside is more salty that the water outside water can move through their skin – by osmosis.

      Saltwater fish do drink water.

    • Photo: Francesca Paradisi

      Francesca Paradisi answered on 18 Nov 2014:

      I agree that sea fish drink water but I’m not sure if it’s because they get thirsty! Maybe they just can’t avoid it? Great question!

    • Photo: Ahmed Osman

      Ahmed Osman answered on 18 Nov 2014:

      Dear Tír Na nÓg ,
      thanks for this brilliant Question, I really like it.
      It simply through a process called osmosis. The denser fluids try to disperse into the less dense. So a freshwater fish having its internal organs being more dense than the water around it would have to expel excess water to prevent over saturation of the cells. While in salt water fish the case is different. The surrounding water is denser thus the fish must literally drink like a fish to prevent dehydration.
      Yes. Fish that live in salt water lose moisture from their bodies through osmosis. These fish need to drink lots of water, or they’ll become dehydrated. The extra salt is then simply excreted.
      hope it helps