# Do Otos Catfish require an open surface for air?



## bastage (Dec 21, 2011)

I have 6 & have never noticed any of them at the surface. They always stayed in the bottom 6" of my 37 gallon


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## FlyingHellFish (Nov 5, 2011)

He was going up and down the side of the tank yesterday, I thought he needed some air. Is it true their bio-load is relatively small? I'm thinking of adding two more so he won't be so alone.


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## monkeyfish (Jul 5, 2010)

Mine are all over the tank and i see them grab a bite of air quite a bit. I think it'll find the opening when it wants some o2. They are happier in groups though.


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## reignOfFred (Jun 7, 2010)

As long as the water itself contains oxygen there are no fish that 'need' to rise for air - not otos or corys or gouramis or bettas. All of then have gills.


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## Gtdad2 (Nov 21, 2010)

reignOfFred said:


> As long as the water itself contains oxygen there are no fish that 'need' to rise for air - not otos or corys or gouramis or bettas. All of then have gills.


^^This, I do not agree with. While they do have gills, like any other fish, they also need to breathe atmospheric oxygen. I used to keep the water level very near my glass top on my 10g with otos. I lowered it to the bottom of the top rim after hearing the otos thump the glass everytime they went up for air.


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## StygianSteel (Apr 2, 2010)

Otos don't NEED to surface for air, but they do appreciate the option. Especially in a tank without a lot of oxygenation.

Disagree about Betas and (most) Gouramis though... most do require breathing from the surface...


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## reignOfFred (Jun 7, 2010)

you don't need to agree, but the fact remains that they can breath oxygen from the water like any fish.


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## Gtdad2 (Nov 21, 2010)

You can also keep a betta (or oto) alive in a half a cup of water...not recommended, however.


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## aweeby (Oct 1, 2011)

not going to say anything about the surfacing, but whenever my otos get startled, they race up and down the glass like mad, like you described. My guess is that they're just stressed out. I wouldn't worry.


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## twospoos (Sep 25, 2011)

I just purchased two otos and have yet to see them even close to the surface. One thing that I will say is these little guys have incredible work ethic. After one nights work, I woke up to find my anubias (as well as the other plants) looking like mighty maids had been in the tank for a nooks and crannies cleaning.


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## wendyjo (Feb 20, 2009)

I've never seen my otos go to the surface for air. He may see his reflection in the glass and that is why he is acting bizarre - this is common for new fish. Also, get a few more as they prefer to be in groups. And yes, they have a small bioload.


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## StygianSteel (Apr 2, 2010)

reignOfFred said:


> you don't need to agree, but the fact remains that they can breath oxygen from the water like any fish.


*Technically*, you are correct. There's a huge difference between can and should. It's not natural for Bettas/most Gouramis to get all their air from the water. Not recommended for optimal health from all I've ever read/seen. If there is no access to the surface/air and the water isn't oxygenated enough this can lead to a Betta/Gourami actually drowning.


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## StygianSteel (Apr 2, 2010)

Gtdad2 said:


> You can also keep a betta (or oto) alive in a half a cup of water...not recommended, however.


Exactly...


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## FlyingHellFish (Nov 5, 2011)

blah!


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## reignOfFred (Jun 7, 2010)

Lol. betta and gourami developed the ability to breath from air to deal with situations such as the dry season. When the water is flowing and oxygen rich, they can breath the water like any fish. i guess I'm the only one who understands this.


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## StygianSteel (Apr 2, 2010)

reignOfFred said:


> Lol. betta and gourami developed the ability to breath from air to deal with situations such as the dry season. When the water is flowing and oxygen rich, they can breath the water like any fish. i guess I'm the only one who understands this.


Guess so


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## wendyjo (Feb 20, 2009)

There have been many reports of bettas getting stuck in a piece of decor and dying because they couldn't get to the surface. Of course, this can't be proven cause if you saw your betta stuck in something you would help get him out. But I highly doubt that these bettas are dying and then getting stuck in something, or that they are dying from injuries sustained while being stuck.


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## Gtdad2 (Nov 21, 2010)

reignOfFred said:


> Lol. betta and gourami developed the ability to breath from air to deal with situations such as the dry season. When the water is flowing and oxygen rich, they can breath the water like any fish. i guess I'm the only one who understands this.


Huh...I wonder why they even bother to breathe from the surface in my well filtered tanks. Guess they don't understand it yet either. LOL


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## Wyomingite (May 25, 2011)

reignOfFred said:


> Lol. betta and gourami developed the ability to breath from air to deal with situations such as the dry season. When the water is flowing and oxygen rich, they can breath the water like any fish. i guess I'm the only one who understands this.


Well, methinks yer rather stubborn 'bout holdin' on to this concept. :icon_wink Might I recommend Air-Breathing Fishes: Evolution, Diversity and Adaptation by Jeffrey B. Graham.

Just off the top of my head, numerous species of gourami, betta, snakeheads, eels, clariid catfish, and _Arapaima gigas_ are *obligate* air-breathers, i.e. their gills have atrophied to the point that the gill surface area is inadequate to sustain sufficient gas exchange for the fish to survive by "breathing" water alone. These fish, although they do utilize their gills like other fish, can not do so efficiently enough to sustain life. If they are denied access to surface air, they suffocate. With these fish, the amount of dissolved oxygen in the water is irrelevant, the gills cannot absorb enough oxygen and/or disperse enough carbon dioxide to live due to the reduced gill surface regardless of how much oxygen is in the water.

On the other hand, Loricariid catfish and Corydoras species, as well as some labyrinth fish, are *facultative* air-breathers, i.e. they have an auxilary method to "breath" air when dissolved oxygen is low and have no need to breath from the surface when dissolved oxygen in the water is adequate. They can survive perfectly well on the gas exchanged in the gills alone under most circumstances. However, instinctive behavior will often continue even when there is adequate dissolved oxygen. Thus cories make their mad dashes to the surface and back down regardless of water conditions. 

To confuzzle matters worse, environmental and chemical factors can force a species to be a facultative air-breather in one set of conditions, and an obligate air-breather in another. The blue gourami, _Trichogaster trichopterus_, for example, is a facultative air-breather below about 70° and an obligate air-breather above that. ("Bimodal Gas Exchange During Variation in Environmental Oxygen and Carbon Dioxide in the Air Breathing Fish _Trichogaster trichopterus_"; Burggren, 1979).

So though you are not wrong, reignofFred, your understanding is incomplete. The physiology of air-breathing fishes is not that easily segregated.

Cheers,

WYite


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## FlyingHellFish (Nov 5, 2011)

No need to argue fellas, Otos is dead.  

Most expensive cleaning service, thanks little guy for giving your life to clean my glass. God, sometimes I hate this hobby. He looked really good, colour was great. Argh.


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## james0816 (Jun 26, 2008)

Well Poo! Sry to hear that.


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## StygianSteel (Apr 2, 2010)

FlyingHellFish said:


> No need to argue fellas, Otos is dead.
> 
> Most expensive cleaning service, thanks little guy for giving your life to clean my glass. God, sometimes I hate this hobby. He looked really good, colour was great. Argh.


Sorry to hear that. They can be pretty hard to introduce. Touchy fish. They'll seem like they're fine for awhile then just drop. It's a fairly common problem. They're great if you can get them to last... I have a couple in my 10 gallon.


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