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16 January 2018, 16:31
The Mystery Hour
Name: Richard, Hoddesdon
Question: Do fish get thirsty?
Name: Robin, Bedford
Qualification: O Level and S Level in Biology
Answer: It Depends whether it is a freshwater or salt water fish.
Fish skin is a semi permeable membrane.
If it is a freshwater fish it is constantly gaining water through its skin so it does not need to drink.
However with a salt water fish the reverse is true; because sea water is more concentrated than its tissues, it is constantly losing water to the sea so it is having to drink the whole time and excrete the excess salt.
In conclusion, A salt water fish gets thirsty the whole time and has to drink.