Yawning fish?

i dont really think they are gasping for air, the feeders i put in there last for a while and they dont do this. but mostly the arapaimas do this while in the middle of the tank, ive seen the bichir do this only three times and there are enough plants (what i think is enough) so the water is oxygenated enough. And they do come to the surface for air when they need it.
 
Yawning

Most of my cichlids yawn at one time or another.

Even the fish in the store do it. I personally don't think it is really yawning but for lack of a better descripton yawning works.
 
I had some cichlids for about a week (bought a tank with cichlids in it, subsequently gave them away) and they would "yawn" too. It looked just like a person yawning, they'd open their mouths all the way for about 1 sec, then go back to normal breathing. I noticed my red zebra and auratus doing it the most of any of then.
 
Every fish I have ever owned has yawned at one time or another. As far as I can tell they yawn for the same reasons people do.
 
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