Questions tagged [ichthyology]

Questions relating to the study of fish or icthyology.

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11
votes
1answer
4k views

Do fish break a water molecule to absorb oxygen?

How do fish separate oxygen from H20 & consume it? Do they break the water molecule and absorb the oxygen only?
6
votes
1answer
1k views

How do sharks and other fish conserve and gain water in marine environments?

With the osmolarity of the average vertebrate being around 300mOsml, and salt water having an osmolarity of 1000mOsml, why does the water from the shark not leave to the salt water around it? I ...
13
votes
1answer
3k views

Can you get enough water by eating only fish?

Scenario: In a boat in the middle of the sea, no freshwater or food stores, no desalination equipment, no rain, but you can catch fish and eat it raw. Can you get enough water this way to survive, let'...
6
votes
2answers
963 views

Why are most fishes vertical?

Why do most fishes have a "vertical" body shape instead of a "flat" one ? Here "vertical" means that the body(from a front view) is roughly orthogonal to the horizontal plane, and a "flat" body shape ...
6
votes
2answers
5k views

In practice, do fishes die from old age?

I was watching sea birds eating fishes and wondered if fishes actually died from old age, or if they are all eaten before this can happen? I reckon some big predator fishes must be able to live long ...
5
votes
1answer
1k views

How does anadromous fish physiology “know” to switch from salt to freshwater and back?

What mechanism allows anadromous fish (like salmon) to switch from salt to fresh water and back? How does the fish "know" to switch its physiology and do other fish possess the biochemical machinery ...
1
vote
1answer
637 views

Breathing under water

Why can fish breathe under water but land mammals can't? How can fish extract oxygen straight from water but humans can't?