Devastated, lost most of my pond goldfish

[bettasngoldfish]

I wanted to ask how Shamu was, but was afraid to bring it up. Glad he and one other are hanging in there!

thank you cas

I was so happy to see her swimming around the pond and then when I saw she still had a buddy I felt even better.

I appreciate all the comments and concern and will keep you posted

 

[Tula]

So happy you still have Shamu and a little buddy

 

[addy1]

Nothing worse than losing fish and having no clue why. So glad shamu made it.

 

[C-Note]

Wow, really sorry to hear about this. It's very sad to lose a crew of fish you've spent so much time caring for.

I have had large losses in the past from oxygen depletion (when I had a much-too-small pond), but it sounds like your situation is not that similar to what I experienced. 1. temps were much warmer. 2. the larger fish were definitely affected first. 3. happened much faster, over the course of maybe 1-2 days tops.

I really hope you are able to sort out the issue, and keep Shamu and the other guy alive!!

 

[Mmathis]

Maria, sorry to be so late responding, but have been out of town. I sure hate to hear this -- how devastating! The first thing I thought of was a lightening strike. I have lost several fish this year, and all of the deaths were as mysterious as yours. The only common denominator was that a thunderstorm had preceded each death or series of deaths. I guess there's no way to be sure, but I'm now highly suspicious of lightening! I wondered why, if it was lightening, was it so selective in the fish that were affected -- wouldn't lightening "fry" the entire pond? I couldn't find a lot of factual information, but did learn that the fish that were closer to the actual strike were much more likely to be injured than those farther away -- so it's not an equal distribution. I felt like my deaths weren't caused by O2 deprivation as it was my smaller to med. sized fish that died, not the larger ones.

I sure wish you COULD know what happened! I'm crying right along with you.....!

 

[Dave 54]

Maria, sorry to be so late responding, but have been out of town. I sure hate to hear this -- how devastating! The first thing I thought of was a lightening strike. I have lost several fish this year, and all of the deaths were as mysterious as yours. The only common denominator was that a thunderstorm had preceded each death or series of deaths. I guess there's no way to be sure, but I'm now highly suspicious of lightening! I wondered why, if it was lightening, was it so selective in the fish that were affected -- wouldn't lightening "fry" the entire pond? I couldn't find a lot of factual information, but did learn that the fish that were closer to the actual strike were much more likely to be injured than those farther away -- so it's not an equal distribution. I felt like my deaths weren't caused by O2 deprivation as it was my smaller to med. sized fish that died, not the larger ones.

I sure wish you COULD know what happened! I'm crying right along with you.....!

As you saw with our three koi Maggie the three nearest to the actual charge coming into our pond are the worst injured , the rest probably recieved a shock but not to the magnitude those three unlucky koi of ours did.
If it wasnt O2 deprivation with your own fish what was it ?
How does this type of fish kill/major die off occurs
During summer, the heat and relatively calm weather causes pond water to stratify into layers.
There is a less dense, warm, upper layer that is exposed to the sun and atmospheric oxygen called the [epilimnion].
There is a very thin layer where temperature and density changes rapidly called the [metalimnion] .
Then a cold, denser, lower layer that receives little sunlight and does not mix with the upper layers [hypolimnion]. Because it does not mix, the hypolimnion has no incoming oxygen to replace what is used by bacteria that are decomposing leaves and plants on the bottom of the pond.
As the summer progresses, the hypolimnion usually loses its oxygen now If a storm carrying cold rains causes the pond to turn over [mix suddenly], then the de-oxygenated water in the hypolimnion can reduce the oxygen level of the pond enough to cause a fish kill/major die off.
Meyer says this cannot happen in non natural ponds but weve heard of these sudden die offs many a time in the last 28 years for it not to happen too both .
Thats the science of it @bettasngoldfish,@Mmathis



Dave

 

[bettasngoldfish]

thank you C-Note and Maggie

I'm still in a bit of shock that they are gone. Every time I go out to look at the pond and I don't see there little faces poking out looking for food I am reminded that they are gone.....

Did some work around the pond on Sunday, cleaned up some plants around the pond area, did another water change on the pond as well as the stock tank, thinned out the plants growing in the waterfall area, removed all the water hyacinth (just in case too many plants were part of the issue) checked all the filters and pumps to make sure everything is in proper working order. Then I decided to move two very small orange and white comets to the pond from the stock tank. If all goes well (and I'm hoping it will) then I will add more fish.

Of course it rained fairly heavy last night again and had me worrying about the pond again. I'm thinking this is going to take me a while to get over completely. I feel like I have lost my confidence in keeping fish (at least outdoors anyway)

 

[Mmathis]

@Dave 54 When we were SCUBA certified a few years back, we learned about thermoclines -- basically layering. However, and I don't recall the numbers, thermoclines don't happen in the relatively shallow depths of the average backyard pond. We're talking depths like 20-30 feet and more. Not saying there aren't differences in our ponds, but I just can't believe that a 3' deep pond that has good water movement is going to suffer from the same things a natural pond is, and to the same extent.

 

[Dave 54]

@Mmathis this also happens in ponds I'm well aware of thermoclines in the sea as the submarines I was paid to hunt would hide out in a thermocline to aviod detection from sonar .
Howver this also can occure in ponds :-

http://www.livingwateraeration.com/beofimpoae.html

As you can see its the cause of fish deaths especially after a heavy rain storm


Dave

 

[Meyer Jordan]

@Dave 54 When we were SCUBA certified a few years back, we learned about thermoclines -- basically layering. However, and I don't recall the numbers, thermoclines don't happen in the relatively shallow depths of the average backyard pond. We're talking depths like 20-30 feet and more. Not saying there aren't differences in our ponds, but I just can't believe that a 3' deep pond that has good water movement is going to suffer from the same things a natural pond is, and to the same extent.

And you are absolutely correct.
Although stratification can occur in shallow ponds it is usually rare, a warm weather event, and always short lived.


"Shallow ponds (perhaps < 8 feet) may not stratify or
may only stratify occasionally and briefly." Ohio State University Extension

"The duration of thermal stratification depends on pond depth and weather conditions. Ponds not
not over 6ft deep usually stratify on warm days, but at night surface waters cool by convection,
and even light winds can cause the entire body of water to circulate."
Hydrology and Water Supply for Pond Aquaculture, Kyung H. Loo, Claude E. Boyd

"...ponds with average depths of about 1 m and maximum depths of 1.2-1.5 m on the Auburn University Fisheries Research Unit, Auburn, Alabama, stratify thermally during warm days only to destratify at night when upper layers of water cool by conduction."
Bottom Soils, Sediment, and Pond Aquaculture Claude E.Boyd

Warm weather stratification in shallow ponds, if it does occur, is at its maximum between 2:00 PM and 4:00 PM when cooling of the upper layer (epilimnion) commences. The relative short duration of this stratification does not allow enough time for any dangerous reduction in DO levels.

As relates to rain showers and thunderstorms, the cooling effect of the precipitation would negate any stratification occurring.

Add to this the fact that many garden ponds have bottom aeration, the mixing of the water as a result of this aeration would effectively prevent any possible stratification.

Bottom line: Thermal stratification is not an issue of any real concern in a garden pond.

 

[Dave 54]

I fully understand what your saying Meyer but catastophic loss of fish lives cannot be blamed on anything else including run off .
Weather patterns around the world are changing , we had almost half the rain for August over Plymouth a few days ago from a system stalled over the UK .
If a pond gas had all day in warm summer weather to heat up it will cause it to stratisfy then along comes the thunderstorm to tip the balance and the pond turns over .
I dont think I'm wrong on this , as I've heard this happen time and time again it always happens on a warm to hot day a warm night then a thundestorm happens during the night, then dead fish.
I would have argued black is blue that my pond wasnt hit by lightening but as we went through each possibility it came back to one thing lightening .
Fish die because they cannot breath which means theres no oxygen in the water, so please pray tell where did it go..... the only way is out of the pond, it happens long enough to take out all but two fish ?

Dave

 

[Dave 54]

May I quote this please Meyer ?

What causes a turnover?
Turnovers occur naturally in the fall. The incremental drop in air temperature slowly decreases the surface water temperature, and the layers in the pond mix gradually. This gradual mixing rarely causes a fish kill. On the other hand, rapid turnover can cause a fish kill. Rapid turnovers can occur anytime during the warmer months of the year when ponds are stratified and they most often coincide with storm events or windy days. A cold rain or the blowing winds of a storm front can cause rapid mixing and result in a fish kill if the pond is stratified.

for full fact sheet see bellow:-

http://www.clemson.edu/extension/na...r_ponds/problem_solving/aeration_circulation/


Summerkill
The Summer Oxygen Cycle

Oxygen production resulting from photosynthesis is highest during summer. This is because warm water and long hours of daylight maximize the amount of algae and aquatic plants in ponds. However, oxygen-using processes, including animal and plant respiration and organic matter decomposition are also at their highest levels in summer. In most ponds, the oxygen produced during daylight far exceeds the amount used by decomposition and respiration, especially at night. As long as daytime oxygen production exceeds nighttime oxygen use, summer fish kills due to insufficient oxygen will not occur. However, there are summer situations that can occur that can lead to fish kills.

How Summerkill Occurs

Excessive Vegetation Scenario—Many Ohio ponds become "choked" with vegetation during July and August. Fortunately, excessive vegetation by itself will not cause a fish kill as the high amount of oxygen produced during daylight easily compensates for respiration and decomposition. Problems can arise during a hot, calm, and cloudy weather pattern. A substantial reduction in sunlight causes the amount of oxygen produced to decline while oxygen consumption remains unchanged. Thus, oxygen levels slowly decline. Ponds can usually withstand several consecutive cloudy days but if clouds persist for longer periods, oxygen levels may decline to levels harmful to fish life, about 3-4 ppm for largemouth bass and bluegills. A fish kill due to insufficient oxygen may begin to occur, particularly just before sunrise when daily oxygen levels are at their lowest. The first fish to die are the larger individuals as their oxygen needs are greater. Fortunately, a sunny day will quickly raise oxygen levels and end the fish kill. A common result of this scenario is a partial fish kill which leaves the pond's fish community dominated by small fish.

Late-Summer Herbicide Treatment—Many owners prefer to have minimal vegetation but wait until the pond has become choked with plants before initiating any control measures. This can lead to a serious oxygen problem if all the vegetation is treated simultaneously with an herbicide/algaecide. Soon after treatment, a massive die-off of the treated vegetation will occur. The actual timing of the die-off depends on the herbicide used and other conditions. But once die-off begins, it proceeds rapidly. This causes a substantial build-up of organic material that begins to decay in the warm water, and which requires large amounts of oxygen to complete. Coinciding with the die-off is a decline in oxygen production as the plants responsible for that production are now lying dead on the pond bottom. Oxygen consumption far outpaces oxygen production and levels begin to decline significantly. Couple this situation with a calm, cloudy day or two, and a fish kill can occur.

Premature Fall Turnover—Any pond that stratifies during summer will undergo a normal fall turnover as water temperatures decline. This process is described in Ohio State University Extension Fact Sheet A-7-01, Understanding Pond Stratification. A fish kill can result in some ponds that experience a premature turnover in late summer.

Many ponds are stratified in summer, with a warm, upper layer of water on top of a colder, bottom layer. These layers do not usually mix until fall. In Ohio's productive ponds, a substantial amount of organic matter accumulates in the deeper areas. The decomposition of this matter results in the colder, bottom layer eventually losing most, if not all, of its oxygen by August. This is not a problem unless the pond turns over in August or September.

Figure 2. Oxygen depletion scenario during premature turnover during summer. Oxygen levels expressed as parts per million (ppm) and show generalized levels and trends.



This premature mixing can be brought on by a heavy, cold rain. Figure 2 illustrates how premature turnover in summer results in a fish kill. In many ponds, the volume of the colder, oxygen-deficient bottom layer of water exceeds the volume of the oxygenated, upper layer. In a heavy rain event (several inches in just a few hours), the cold rain water plunges through the warm upper layer towards the bottom. This is because cold water is denser than warm water and therefore sinks. This rain event can cause the entire pond to mix. The mixing of oxygen-deficient water with the oxygenated water can occasionally cause oxygen to fall to levels lethal to fish.

A heavy rain event can also cause a stratified pond to mix in another manner. A large inflow of cold rain water from watershed runoff can also cause a sudden mixing of oxygen-deficient water with oxygenated water. Depending on the volume of the two layers, a fish kill may result. Ponds with a very large watershed are more prone to this scenario.

Premature turnovers are not a problem in June or after September. In June, stratification has just occurred and the colder, bottom layer still contains oxygen. While that oxygen level may be slowly declining, a sudden mixing does not result in low oxygen levels throughout the pond. Premature turnovers generally do not cause a problem until late July. After mid-September, pond temperatures begin cooling. Colder surface water holds substantial oxygen which allows the pond to more easily withstand turnover effects. Additionally, as temperatures decrease, the very distinct stratification diminishes which slowly allows oxygen to be re-introduced into the deeper waters.

Worst Case Scenario—The likelihood and severity of a summer fish kill is increased if the scenarios described above occur in conjunction with each other. For example, if a pond treated with an aquatic herbicide in late-July or August receives a heavy inflow of cold rain water, a fish kill is likely. This is because a very large quantity of dead plant material is decaying. A sudden turnover results in the upper layer oxygen being mixed throughout the pond where it is quickly consumed by the decomposing plants. The situation is further worsened because the pond has fewer oxygen-producing plants.

Factors Influencing the Likelihood of a Summerkill

Vegetation Biomass—The quantity of vegetation in August and September plays an important role in the likelihood of a fish kill. Vegetation-choked ponds are much more likely to experience problems than a pond with little or no vegetation.

Weather—As described previously, weather plays a critical role in whether a summer fish kill will occur. A cool summer marked by breezy conditions generally reduces the chances of a summer fish kill. Conversely, a calm, hot summer or a cloudy summer increases the likelihood.

Pond Size and Depth—These factors influence the likelihood and severity of a premature turnover causing a fish kill. Small, very deep ponds (more than 12 feet) are more susceptible to the effects of a premature turnover than are large, shallow ponds. This is because a small, deep pond has a higher proportion of the water that lacks oxygen as compared to a larger, shallower pond. If the ponds turn over, oxygen may decline to near zero in the deep pond but often remain high enough in the larger, shallow pond to keep fish alive. A large, windswept pond in an open area rarely stratifies because of the continual mixing and usually does not experience problems associated with a premature turnover.

Summerkill Prevention

Just as for winter fish kills, there are activities the pond owner can undertake to prevent a summer fish kill. As noted previously, ponds should have shoreline slopes of 3:1 to limit summer aquatic plant growth to the areas near shore. The reduced amount of summer aquatic vegetation means more balanced levels of oxygen between day and night. While oxygen production during the day may not be as great, plant respiration (oxygen consuming) at night will be greatly reduced. This prevents pre-dawn oxygen levels from plunging to lethal levels for fish.

In existing ponds, any early summer strategy that reduces the amount of plant growth is beneficial. This is particularly true for those ponds having a history of dense aquatic vegetation and/or may have had summer fish kills in previous years. If an herbicide/algaecide is used to eliminate or reduce summer aquatic vegetation, applications should be completed before July 1. Later applications run the risk of indirectly causing a fish kill as described earlier.

In situations where the pond owner decides late-season herbicide control is needed, the pond should be treated in sections. Granular formulations of herbicides allow for control in specified areas. Treat about 1/4 of the pond every 2-3 weeks, starting with the area where control is most important (e.g., swimming area). This spreads decomposition over a longer period of time as compared to total pond vegetation control with a liquid herbicide.

Perhaps the most effective way to prevent summer fish kills is to install an aeration system. Aeration serves to minimize the risk of a fish kill in several ways. First, aeration continuously adds oxygen to the water, which is important if oxygen begins to approach critically low levels. Fish will find the oxygenated water around the aerator. Secondly, aeration often prevents summer stratification from occurring. If the pond is not stratified, premature turnover will not occur. Finally, aeration keeps nutrients suspended which promotes single-cell algae growth. This reduces aquatic vegetation density due to the shading effect of green pond water. Most Ohio ponds do not require aeration during normal summers, but more pond owners are installing them as a preventative measure. Aeration does not need to be a 365 days, 24 hours a day activity. Using aeration at night during the May to September period will prevent summer fish kills.

A common type of aeration that many pond owners are installing is a windmill system in which wind power generates the aeration in the pond. While these systems can reduce the chances of a fish kill as long as a breeze is blowing, they are useless in those calm, cloudy, late-summer weather patterns that can lead to a summerkill. If these systems are installed, a pond owner would be well-advised to consider having the system equipped with the capability of using electricity to generate aeration as a back-up.

For full fact sheet see bellow :-

http://ohioline.osu.edu/a-fact/0008.html

Dave

 

[Big Lou]

I hope don't either.

 

[Meyer Jordan]

This is because a small, deep pond has a higher proportion of the water that lacks oxygen as compared to a larger, shallower pond. If the ponds turn over, oxygen may decline to near zero in the deep pond but often remain high enough in the larger, shallow pond to keep fish alive.

Dave, everything that you have cited is absolutely true as relates to ponds that are generally deeper than 8 feet. These ponds will remain stratified for weeks and the sudden cooling effect of a thunderstorm can potentially cause an unexpected turnover which in turn may result in a fish kill. Read the highlighted portion of the above quote.
It all relates to depth. And if your pond has bottom aeration, it will not stratify regardless of depth.

 

[MitchM]

My pond is 5 feet deep and I have temperature sensors at 2 foot and 5 foot depths.
With water circulation, there is no temperature difference.