First of all, a fish opens its mouth and water enters which passes through its gills. This helps in oxygenating its blood. So, if any food particle is in its mouth, how can it "breathe" i.e. how does exchange of gases occur? Shouldn't the pathway where water flows from mouth to gills be clogged like a drain full of sludge?

  • $\begingroup$ Food particles don't just sit around in the mouth; they go from the mouth to the stomach. I would expect most animals can survive a lack of oxygen intake for the mere seconds it takes for the food to move on. In any case, according to the Florida Museum of Natural History, fish generally do not chew their food, so the pathways should not be "clogged like a drain full of sludge". $\endgroup$ – Harris May 3 '17 at 17:50

They can pump water over their gills with their opercular flaps (i.e., the structure that covers and protects the gills). This is assisted by the branchiostegal rays. Food would generally not interfere with this process. Additionally, gill rakers assist in keeping food in the mouth.

Some great references for questions like this:

Barton, M., & Bond, C. E. (2007). Bond's biology of fishes. Thomson.

Moyle, P. B., & Cech, J. J. (2004). Fishes: an introduction to ichthyology (Vol. 726). Upper Saddle River, NJ: Pearson Prentice Hall.

  • $\begingroup$ Please update your answer by citing and/or summarizing supporting evidence from reputable sources. Thanks. $\endgroup$ – theforestecologist Mar 19 at 14:53
  • 3
    $\begingroup$ regardless of your own legitimacy, the internet doesn't know that about you (nor should users passing through necessarily believe that about you -- there are plenty of "fake" experts out there). Having a more formal source of info allows users to check in on the legitimacy of something more completely & objectively. It also enables them to use your source as a doorway to learning more about the topic. Take a look through Yahoo answers or Quora and see how many "legitimate" answers from "experts" are wrong -- without regular citing practices, users will never know one way or the other $\endgroup$ – theforestecologist Mar 19 at 16:56
  • 1
    $\begingroup$ I have added 2 sources, besides my own personal expertise as a fisheries research biologist $\endgroup$ – OliverFishCode Mar 19 at 16:57
  • $\begingroup$ @theforestecologist You made a good point, thus, I have added to my response $\endgroup$ – OliverFishCode Mar 19 at 17:07
  • $\begingroup$ Thanks very much. We're here to educate, so doing our best and most thorough job is worth that extra effort! :D. +1. $\endgroup$ – theforestecologist Mar 19 at 17:16

Fish that are filter feeders generally have Gill Rakers which prevent food from actually damaging and clogging the gills.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.