Catfish dead. Koi nowhere in site

[brokensword]

Wow, I really hope the catfish did not die b/c of oxygen starvation. I would think that aerator would have been adequate. The waterfalls are shut down because the bloody things leak and no matter who we hire to fix the problem, they still leak. The guy who rebuilt the pond cannot find the source of the leak.

This is the first year the waterfalls have been off. The aerator is new. I'd better call the guy and see what he says. Thanks for the input, everyone.

Colleen, where did you get a camera small enough to fit into a jar?

FF: I hope Meyer will confirm this but an aerator doesn't add much O2 to the water column. It is the disturbance it creates at the top, the surface to air exchange that is important, hence why waterfalls work so well in this regard. In the winter, the aerator is to help keep a hole open in the ice as whatever is decaying in the pond will suck up some of the available oxygen on its way to releasing toxic gasses. Again, I hope Meyer will confirm or correct this assertion.

Michael

 

[Meyer Jordan]

FF: I hope Meyer will confirm this but an aerator doesn't add much O2 to the water column. It is the disturbance it creates at the top, the surface to air exchange that is important, hence why waterfalls work so well in this regard. In the winter, the aerator is to help keep a hole open in the ice as whatever is decaying in the pond will suck up some of the available oxygen on its way to releasing toxic gasses. Again, I hope Meyer will confirm or correct this assertion.

Michael

Essentially that is correct.

 

[Usman]

Is the netting disturbed? Is the pond frozen on top mostly? Maybe its an oxygen problem... big catfish would be the first to go...

most of the catfishes are very tuff they can live in low oxygen and bad quality of water , some times it would come up to breathe

 

[Usman]

I'm not questioning that you have neighborhood hooligans, but catching koi is no easy task even for an experienced pond owner. Is it possible you had a visit from a mink? A mink will even go under the ice to get fish, so a net would be no trouble at all. We met a pond owner who had his pond cleared of 30+ koi over night by a hungry mink. Just a thought...

i was thinking same its time consuming to catch a fish and in winters they are at bottom

 

[callingcolleen1]

@callingcolleen1, so did you weigh the jar down with something when you put the jar containing the camera in the water? Did you set the camera to take a bunch of photos or did you take a recording?

I've left a message for the guy who rebuilt the pond and told him about the dead catfish and disappeared koi.

I just used my hand and lowered the jar down. You could use something to weigh it down, but I would strongly recommend you just drain half the water at the very least and get to the bottom of pond as you have no signs of life.

 

[Usman]

FF: I hope Meyer will confirm this but an aerator doesn't add much O2 to the water column. It is the disturbance it creates at the top, the surface to air exchange that is important, hence why waterfalls work so well in this regard. In the winter, the aerator is to help keep a hole open in the ice as whatever is decaying in the pond will suck up some of the available oxygen on its way to releasing toxic gasses. Again, I hope Meyer will confirm or correct this assertion.

Michael

Essentially that is correct.

Air Bubbles Do Actively Aerate - myths-that-need-to-die
http://advancedaquariumconcepts.com/air-bubbles-do-actively-aerate/

 

[Meyer Jordan]

Air Bubbles Do Actively Aerate - myths-that-need-to-die
http://advancedaquariumconcepts.com/air-bubbles-do-actively-aerate/

Of course air bubbles do provide active sub-surface aeration. But there is more to the process of aeration than a simple general statement. The actual efficiency of sub-surface aeration whether by air stone or diffuser is determined by the depth of the body of water and the size of the bubbles. Even the most efficient system will not add much Oxygen by transference from the rising bubbles in comparison to the Oxygen transfer achieved at the water-atmosphere interface as a result of the mixing action imparted upon the water column by this same column of rising bubbles. So essentially Brokensword is correct in his assumption.
Waterfalls are actually more efficient at adding Oxygen to a body of water but the downside is that this oxygenation is confined to an area immediately surrounding the waterfall and is not spread evenly throughout the water column. This is one of the reasons that one will find fish congregated at the base of a waterfall. It is not that the pond has low Oxygen but that the water in this area is much more heavily oxygenated.

A few assorted cites-
"However, almost all of the oxygen dissolved into the water from an air bubble occurs when the bubble is being formed. Only a negligible amount occurs during the bubbles transit to
the surface of the water."
Water Aeration---Wikipedia

"Many People are surprised to learn that the majorioty of oxxygenation occurs through the water's contact with the atmosphere, relatively little increase occurs through direct
diffusion from bubbles."
Lake Notes--Illinois Environmental Protection Agency

"Synergistic airlifts are at the other end of the spectrum because they expend very little energy and circulate huge quantities of water upward. In this case, the interaction at the
surface of the lake adds to the majority of the oxygen added to the water."
Pentair Aquatic Ecosystems

"Fine-bubble, bottom-laid aeration also moves the most water at the lowest cost. By producing a gentle, laminar flow of small bubbles, at a consistent rate of rise, water
molecules are moved easily to the surface, where oxygenation occurs."
and-
"Aerators that create coarse bubbles, such as air stones and flex diffusers, employ an uncontrolled release of air, which has been shown to be much less effective at moving water compared to fine-bubbles.
Principles of Aeration- EPAeration

 

[brokensword]

Of course air bubbles do provide active sub-surface aeration. But there is more to the process of aeration than a simple general statement. The actual efficiency of sub-surface aeration whether by air stone or diffuser is determined by the depth of the body of water and the size of the bubbles. Even the most efficient system will not add much Oxygen by transference from the rising bubbles in comparison to the Oxygen transfer achieved at the water-atmosphere interface as a result of the mixing action imparted upon the water column by this same column of rising bubbles. So essentially Brokensword is correct in his assumption.
Waterfalls are actually more efficient at adding Oxygen to a body of water but the downside is that this oxygenation is confined to an area immediately surrounding the waterfall and is not spread evenly throughout the water column. This is one of the reasons that one will find fish congregated at the base of a waterfall. It is not that the pond has low Oxygen but that the water in this area is much more heavily oxygenated.

A few assorted cites-
"However, almost all of the oxygen dissolved into the water from an air bubble occurs when the bubble is being formed. Only a negligible amount occurs during the bubbles transit to
the surface of the water."
Water Aeration---Wikipedia

"Many People are surprised to learn that the majorioty of oxxygenation occurs through the water's contact with the atmosphere, relatively little increase occurs through direct
diffusion from bubbles."
Lake Notes--Illinois Environmental Protection Agency

"Synergistic airlifts are at the other end of the spectrum because they expend very little energy and circulate huge quantities of water upward. In this case, the interaction at the
surface of the lake adds to the majority of the oxygen added to the water."
Pentair Aquatic Ecosystems

"Fine-bubble, bottom-laid aeration also moves the most water at the lowest cost. By producing a gentle, laminar flow of small bubbles, at a consistent rate of rise, water
molecules are moved easily to the surface, where oxygenation occurs."
and-
"Aerators that create coarse bubbles, such as air stones and flex diffusers, employ an uncontrolled release of air, which has been shown to be much less effective at moving water compared to fine-bubbles.
Principles of Aeration- EPAeration

Meyer;

Is there a way to calculate, even if approximately, how far from the waterfall this area of more oxygenated water is? I know there must be a lot of factors, but I was wondering if there's a formula or something. Like, how high the fall, how long it's oxygenated, water flow speed, water volume, etc. Maybe much too complex for a simple answer. Is there any example done using oxygen meters to illustrate? And I wonder if you have a submersible pump pulling this same richer-oxygen water through the rest of the pond, does this extend the area? Any way to calculate how much if so?

Any further thoughts/expansion on this would be really interesting. I'm wondering specifically, of course, how 'un-oxygenated one side of my pond is from the other as my fall is set up that way. I did have an aerator on the other side but since reading that aerators don't add much, abandoned it. Would you suggest either another fall or reinstall the aeration on the 'pump' side? And recommended size/stone/lpm etc?

Thanks, Meyer.

Michael

 

[Meyer Jordan]

Meyer;

Is there a way to calculate, even if approximately, how far from the waterfall this area of more oxygenated water is? I know there must be a lot of factors, but I was wondering if there's a formula or something. Like, how high the fall, how long it's oxygenated, water flow speed, water volume, etc. Maybe much too complex for a simple answer. Is there any example done using oxygen meters to illustrate? And I wonder if you have a submersible pump pulling this same richer-oxygen water through the rest of the pond, does this extend the area? Any way to calculate how much if so?

Any further thoughts/expansion on this would be really interesting. I'm wondering specifically, of course, how 'un-oxygenated one side of my pond is from the other as my fall is set up that way. I did have an aerator on the other side but since reading that aerators don't add much, abandoned it. Would you suggest either another fall or reinstall the aeration on the 'pump' side? And recommended size/stone/lpm etc?

Thanks, Meyer.

Michael

I know of no existing formula or formulae for determining what you are asking but I would bet that there are engineers that would devise something for you.
Seriously though, in a pond with a proper level of circulation (flow rate), the DO saturation rates at the pump intake and the base of the waterfall should not really be large enough to cause concern. Carp (Koi) will do quite well with DO levels as low as 5 mg/l and will survive at levels as low as 3 mg/l.
Biological Oxygen demand (BOD) and Chemical Oxygen demand (COD) are the ultimate determiners of DO levels. Fish load being the typical determining BOD factor although there are many other factors affecting DO demand.
A couple of simple DO tests, one at the waterfall base and one near the pump intake, will provide a fairly clear picture of Oxygen levels in your pond.

 

[brokensword]

Thanks, Meyer. I did some further reading on DO, etc after I posted, so I understand better/more. I wish there was an inexpensive DO meter (as opposed to the liquid test) that I could get as I think this would be an important parameter to monitor. I'm pretty sure most will say my pond is overstocked (approx 100 gf, most 6", some 20 at 12" in 2700 gallons, upflow bog filtration), so I'm trying to augment my situation to avoid calamity and getting rid of fish isn't on the to-do list. Not yet, at least!

Btw, which DO meter would you recommend, brand/type/spec for which I could be on the lookout, used undoubtedly...

Michael

 

[Meyer Jordan]

Thanks, Meyer. I did some further reading on DO, etc after I posted, so I understand better/more. I wish there was an inexpensive DO meter (as opposed to the liquid test) that I could get as I think this would be an important parameter to monitor. I'm pretty sure most will say my pond is overstocked (approx 100 gf, most 6", some 20 at 12" in 2700 gallons, upflow bog filtration), so I'm trying to augment my situation to avoid calamity and getting rid of fish isn't on the to-do list. Not yet, at least!

Btw, which DO meter would you recommend, brand/type/spec for which I could be on the lookout, used undoubtedly...

Michael

Although DO meters are nice because you can get readings faster, I prefer the liquid test. I feel that overall it is more accurate as the meters require calibration frequently and the probes require replacement too often.
Salifert offers the least expensive liquid kit. Others that are more accurate are available at quite a wide range of prices. I would recommend either LaMotte or Hanna. .

 

[Fishfinder]

OK, I have a question - I have read of people shutting down waterfalls in the fall and the fish have been fine in the spring. Maybe because the catfish is a bottom dweller, it did not get much oxygen and died. If the lack of air did kill him, it took a while to do it. The wimpy little stones I bought in the fall have died. I just noticed yesterday. I forgot they were even there.
The koi are still no where to be seen. I had a dream they did appear again, but when I was out there yesterday, none to be found.

I shut the waterfalls down in the first place at the advice of the pond builder because the bloody pond keep leaking. He cannot find the source of the leak. He said we would figure out what to be done in the spring. I can't keep pour money into this watery money pit.

Who has liner under their waterfalls?

I have the worse luck with this pond and with pondbuilders. Do any of them know what they are doing?!

 

[Lisak1]

I have read of people shutting down waterfalls in the fall and the fish have been fine in the spring

So much of this depends on the design of your pond - it's never a one-answer-fits-all situation. Generally yes, you can shut down a pond in the fall and the fish will be fine with some added aeration and/or a way to maintain gas exchange (hole in the ice). However, there are so many factors that come into play, like how big is your pond, how many fish do you have, how deep, how cold, etc. Some people are forced to shut down because their waterfall design won't allow for ice to form without re-routing all the water out of the pond. And as fish get bigger, sometimes what worked for years suddenly spells death - bigger fish equal bigger oxygen requirements and sometimes you find out too late that you hit the tipping point and your fish pay the price. To me, the ideal situation is a pond that can run all winter. But again, that's not always possible based on a pond design or the owners life situation or a myriad of other variables.

Who has liner under their waterfalls?

And my answer to this one would be "everyone"? I guess I'm confused - do you NOT have liner under your waterfall? If not, then you don't have a "leak" - you have a design flaw.

And YES! Lots of pond builders know what they are doing. But there are also many people who pass themselves off as pond builders who are really don't. Seeing their previous jobs and speaking to other customers is your best resource - find out for yourself if they know their business.

 

[Fishfinder]

This builder was recommended by someone who has a pond. He has no problems. I am going to insist on lining under that waterfall.

I just went out and shut off that big aerator, and plugged in the two air stones that were shut off - is that sufficient to supply oxygen? The airstones are not big and certainly not powerful. How deep should they go? The pond of about 3.5 feet deep, 12 long and 7 across - I think.

I'll take some photos in a bit. Time to feed the parrots.
Thanks for your help, Lisak1

 

[Lisak1]

This builder was recommended by someone who has a pond. He has no problems. I am going to insist on lining under that waterfall.

I don't want to put too fine a point on it, but any pond builder who built a waterfall with no liner under it DOESN'T know what they are doing. Like I said - you don't have a "leak" you have a basic design flaw. So I guess that's the good news/bad news scenario.

I'd love to hear how he thinks that waterfall is going to hold water without a liner under it...