Just How Mych Oxygen Do Fish Really Need?

[deftuch]

hi there i have two 180 litre juwel vision tanks. one is heavily stocked and is oxygenated by the ventri syatem on one of the fluval internal filters! both my tanks have the cristalprofi e700 external filters in ( which are incredible filters ) one of the tanks i mentioned also has a fluval u3 internal filter which provides the oxygen via the ventri system. my other tank is only oxygenated by the output flow of the external filter. i have positioned it just above water level so it can create oxygen and also is still quiet! also there is fresh water going in every week too! someone i know has a 60 litre tank and has strockedd 2 silver sharks 3 tiger barbs and a fully grown featherfin catfish and they are all still alive after no oxygen what so ever going into that tank for atleast 3 months! so i begun to think to myself do i really need to put an air pump in my second tank and is a high amount of oxygen neccasarry?

 

[daz4321]

air pumps and air stones provide hardly nothing in terms of oxygen except for the fact that they provide surface movement which is where the gas exchange takes place, as long as the surface of you tank has a ripple there will be enough oxygen in the water providing it is not too seriously overstocked.

 

[mr nelster]

hi there i have two 180 litre juwel vision tanks. one is heavily stocked and is oxygenated by the ventri syatem on one of the fluval internal filters! both my tanks have the cristalprofi e700 external filters in ( which are incredible filters ) one of the tanks i mentioned also has a fluval u3 internal filter which provides the oxygen via the ventri system. my other tank is only oxygenated by the output flow of the external filter. i have positioned it just above water level so it can create oxygen and also is still quiet! also there is fresh water going in every week too! someone i know has a 60 litre tank and has strockedd 2 silver sharks 3 tiger barbs and a fully grown featherfin catfish and they are all still alive after no oxygen what so ever going into that tank for atleast 3 months! so i begun to think to myself do i really need to put an air pump in my second tank and is a high amount of oxygen neccasarry?

I have the same tank and I use a bubble bar buried in the gravel every night for about 30-60 mins and the fish seem to like it, though it may just be breaking up the boredom.


Mine is planted and I read somewhere that too much oxygen isn't beneficial to the plant growth? Didn't really follow it up though it would be nice to know?

 

[daz4321]

too much oxygen is nigh on impossible to get (unless you start using bottled oxygen), for plants low or fluctuating co2 is bad oxygen is no bother.

 

[N0body Of The Goat]

A lot comes down to the fish you have and whether they are able to use air to supplement the oxygen levels in the water. Turbulent riverine fish from around the Malebo Pool area of the Zaire (Congo) River are supposed to need close to 8mg/l, just like many "hillstream loach" species, whereas say a Hoplo Catfish can dash upto the surface of a stagnant pool and absorb oxygen from the air in its gut.

 

[Yanks15]

Are there any requirements/suggestions for keeping Mbuna? I have HOB's and can create some movement by leaving the water level a bit low. Do they like having movement in the water?

Thanks
Steve

 

[tomtomtom1230]

I think most fish can overcome the water movement issue. It's like a runner trying to adapt to swimming for the first time; fish have a muscle system in their bodies that can develop too. Provided you don't have dead spots, rather you have calmer areas of water movement (say, behind an ornament, plant or in a cave) that the fish can use as a respite when it gets tired then you should be fine. You can also look at it this way (although this is a little bit general for most): If the fish is a 'torpedo' shape - ie; long, slender with a dart-shaped head - then it's probably a safe bet to assume that the fish can tolerate a stronger current (see fish such as Danios, Minnows and Tetras). If a fish is round or wider around their 'upper body' near their head then it's also a safe bet to assume that calmer water conditions are called for. As I said, that's quite a general comment and no way replaces good old fashioned googling or reading up on fish.

Mbuna fish have quite wide and flat heads so I would say that they need some current in the water to keep the muscles in their bodies developed enough to cope but not so strong that they need to find a calmer spot. HOB filters generally (unless you're severely over filtering) don't provide a strong enough current to over power fish but again, that's quite a general statement. The best way is to (if possible) adjust the flow on your filter and observe your fish. Are they struggling? Signs of stress? Do they all collect in one corner of the tank where the current is at it's weakest?

 

[deftuch]

wow, thanks for the replies! it seems most of you have said what i though any case! i just wanted to make certain though, and its always fun to start your own topic. and regards the the idea of you cant have too much oxygen, you woudnt be saying that if you saw the tank at my lfs. theres was cloudy white stuff coming out of the filter completely colouring the tank milky white. i thought it was some kind of sanitiser or weird treatment, instead it was just the filter producing too much tiny oxygen bubbles. when i alerted her of it she quickly rushed over ( almost in a panic ) and turned the filter down lol. so i guess thats what made me think about it more lol

I think most fish can overcome the water movement issue. It's like a runner trying to adapt to swimming for the first time; fish have a muscle system in their bodies that can develop too. Provided you don't have dead spots, rather you have calmer areas of water movement (say, behind an ornament, plant or in a cave) that the fish can use as a respite when it gets tired then you should be fine. You can also look at it this way (although this is a little bit general for most): If the fish is a 'torpedo' shape - ie; long, slender with a dart-shaped head - then it's probably a safe bet to assume that the fish can tolerate a stronger current (see fish such as Danios, Minnows and Tetras). If a fish is round or wider around their 'upper body' near their head then it's also a safe bet to assume that calmer water conditions are called for. As I said, that's quite a general comment and no way replaces good old fashioned googling or reading up on fish.

Mbuna fish have quite wide and flat heads so I would say that they need some current in the water to keep the muscles in their bodies developed enough to cope but not so strong that they need to find a calmer spot. HOB filters generally (unless you're severely over filtering) don't provide a strong enough current to over power fish but again, that's quite a general statement. The best way is to (if possible) adjust the flow on your filter and observe your fish. Are they struggling? Signs of stress? Do they all collect in one corner of the tank where the current is at it's weakest?

i dont think we will ever fully understand fish if im honest! its clear fish get tired because they rest. however i have 4 glass catfish in my tank whom all swin together directly in the current of my filter. and not once have i ever seen them rest! they instead work like birds and change leaders every now and again to have a rest. i find this amazing. is there any info what so ever about them doing that cos i coudnt find any!

 

[tomtomtom1230]

wow, thanks for the replies! it seems most of you have said what i though any case! i just wanted to make certain though, and its always fun to start your own topic. and regards the the idea of you cant have too much oxygen, you woudnt be saying that if you saw the tank at my lfs. theres was cloudy white stuff coming out of the filter completely colouring the tank milky white. i thought it was some kind of sanitiser or weird treatment, instead it was just the filter producing too much tiny oxygen bubbles. when i alerted her of it she quickly rushed over ( almost in a panic ) and turned the filter down lol. so i guess thats what made me think about it more lol

I think most fish can overcome the water movement issue. It's like a runner trying to adapt to swimming for the first time; fish have a muscle system in their bodies that can develop too. Provided you don't have dead spots, rather you have calmer areas of water movement (say, behind an ornament, plant or in a cave) that the fish can use as a respite when it gets tired then you should be fine. You can also look at it this way (although this is a little bit general for most): If the fish is a 'torpedo' shape - ie; long, slender with a dart-shaped head - then it's probably a safe bet to assume that the fish can tolerate a stronger current (see fish such as Danios, Minnows and Tetras). If a fish is round or wider around their 'upper body' near their head then it's also a safe bet to assume that calmer water conditions are called for. As I said, that's quite a general comment and no way replaces good old fashioned googling or reading up on fish.

Mbuna fish have quite wide and flat heads so I would say that they need some current in the water to keep the muscles in their bodies developed enough to cope but not so strong that they need to find a calmer spot. HOB filters generally (unless you're severely over filtering) don't provide a strong enough current to over power fish but again, that's quite a general statement. The best way is to (if possible) adjust the flow on your filter and observe your fish. Are they struggling? Signs of stress? Do they all collect in one corner of the tank where the current is at it's weakest?

i dont think we will ever fully understand fish if im honest! its clear fish get tired because they rest. however i have 4 glass catfish in my tank whom all swin together directly in the current of my filter. and not once have i ever seen them rest! they instead work like birds and change leaders every now and again to have a rest. i find this amazing. is there any info what so ever about them doing that cos i coudnt find any!

Glass catfish are a very good indicator of your water movement, they require stiller water conditions as I understand otherwise their feelers can become damaged. Oxygen only gets to a certain stage in the water. Bubbles can 'colour' the water enough if they're in number and small enough. Oxygen can only be dissolved to a certain amount and fish can only utilize a certain amount at a time. As far as I'm aware, it's hard to 'over dose' your water with oxygen because its not very soluble and it is also exchanged at the surface for CO2 and fresh O2. Might be wrong but that's how I understand it. O2 is always entering your water when there's plants and/or surface agitation but it also leaves your water column here, too. I think?