# Fish opening and closing mouths



## AshNeon93 (Jan 11, 2014)

I was just wondering if everyones fish (I'm asking because my neon and rummynose tetra) open and close their mouths quickly all the time, they are not at the surface they are more bottom then top swimming so I don't think its them gasping. Just curious anyway! Thanks.


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## Jace (Feb 20, 2008)

My Cardinal Tetras never did, they would mostly just drift around in the water column looking for food. The only time's I've ever seen fish do that is when I first get them from the pet store. But it's important to ask you, how quickly are they gasping and are they exhibiting any other weird characteristics?


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## DirtDevilDTOM (Nov 10, 2014)

My rainbow fish do this occasionally - parameters always seem fine and nothing changes in the tank when it does. The mouth opens wide and gills flare with it. They only do it a few times and an hour later, they aren't doing it. Always worries me when I see this happen but they always seem to be fine.


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## AshNeon93 (Jan 11, 2014)

Probably 1.5 times per second? They seem perfectly fine behaviour wise, the occasional aggressive charge but this is normal with neon tetra I think, I just looked and all of my fish do it, even the honey gourami who is a air breather, it does worry me though as I'm a bit of a fish-hypochondriac! If they were struggling to breathe would they 100% be at the surface gasping?


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## garfieldnfish (Sep 25, 2010)

I have seen my fish do it on occasion after a water change when I added the water too quickly. They usually return to normal in about one hour. I did have a couple of fish die shortly after they did that even though they had been totally normal before the water change.


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## AshNeon93 (Jan 11, 2014)

garfieldnfish said:


> I have seen my fish do it on occasion after a water change when I added the water too quickly. They usually return to normal in about one hour. I did have a couple of fish die shortly after they did that even though they had been totally normal before the water change.


Mine have done it for weeks, months even. I was just curious to see if it was normal but it appears not to be.


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## Knotyoureality (Aug 3, 2012)

Started seeing this when I switched from a HOB to cannister filter on my community tank. Cannister keeps the tank crystal clear and let me solve a "dead spot" in terms of flow in one corner--but it meant sacrificing surface agitation. Pointing the return upwards to create ripples resolves the gasping behavior within minutes.


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## Betta132 (Nov 29, 2012)

Some fish just breathe more visibly than others. 
Try adding an oxygen source to see if it stops.


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## FewestKitten896 (Dec 13, 2013)

My rummy nose tetra do this also.


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## PhysicsDude55 (Oct 24, 2011)

I keep my tank at a delicate balance with surface agitation. I try to minimize evaporation while having enough 02 for the fish.

I have never personally seen my fish go to the surface for air, but I can certainly tell how oxygenated the water is by how quickly they're breathing. What you're describing sounds exactly like the tank is low on oxygen. A little more surface agitation will do the trick. By the time the fish are gasping at the surface, I think they're in "desperate" mode.


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## Betta132 (Nov 29, 2012)

Fast/visible breathing often means they're kind of panting. It's survivable, just not healthy. Gasping at the surface is the OMG CAN'T BREATHE mode, and that's very bad.


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