Fish dying after topping up pond

[LoeiI]

Hi all I have a small fishing pond (35m x 15m) next to the house and during the dry season the water level falls quite significantly so I topped it up with water that i pumped from my well, over the last few days I've found about 30 to 40 fish floating on the surface, I have a mix of fish species in the pond but all the dead fish are pla tapien, has anybody got any suggestions ? I am assuming it may be lack of oxygen but no other species seem to be affected, any help greatly appreciated TIA

[Dmaxdan]

The fish topping and gasping for air would suggest oxygen levels in the pond are too low.

 

Not all species of fish require the same amount oxygen to survive.

 

Can you not install some sort of pump to constantly agitate the water?

[LoeiI]

25 minutes ago, Dmaxdan said:

The fish topping and gasping for air would suggest oxygen levels in the pond are too low.

 

Not all species of fish require the same amount oxygen to survive.

 

Can you not install some sort of pump to constantly agitate the water?

The ponds been dug for about 4 years and its never happened before, i populated it with fry and they've grown naturally carp catfish pla nin pla ni and pla tapien some up to around 2.5 kilos I suppose it could be getting over populated so maybe more oxygen is required ?. I have noticed the dead fish are quite Red which they aren't normally

[impulse]

When you pumped the water from the well, did you put the end of the hose directly into the pond, or did you spray it into the air to aerate it?

 

Depending on a lot of factors, subterranean water can be depleted of oxygen.  It gets pulled out of the water to react with the surrounding soils, etc.  You can add some back by spraying the water into the air.

 

Edit:  I'd still have the water tested on the outside chance you have arsenic or something else in the well water and the dead fish are the canary in your coal mine.  Could be a message from Heaven...

 

Edited December 15, 2023 by impulse

[kickstart]

How deep is the well, could the water be sightly Salin, water from a well is different from rain fed, some fish do not like a change of water supply I know Bla Dok, walking catfish, do not like a change of water.

We have a pond and pump water on to the fruit trees a veg in the garden, during the dry season not enough water in the pond so the wife uses mains water from underground supply, some of the fruit trees start not look too well, soon as the rains come, they pick up. 

[LoeiI]

3 hours ago, impulse said:

When you pumped the water from the well, did you put the end of the hose directly into the pond, or did you spray it into the air to aerate it?

 

Depending on a lot of factors, subterranean water can be depleted of oxygen.  It gets pulled out of the water to react with the surrounding soils, etc.  You can add some back by spraying the water into the air.

 

Edit:  I'd still have the water tested on the outside chance you have arsenic or something else in the well water and the dead fish are the canary in your coal mine.  Could be a message from Heaven...

 

I now use the well water for the house supply (I got a water filter fitted and the bloke tested the well water and the supply from the village tower and said the well water was much cleaner) the water i pumped into the pond didn't go through the filters but straight from the well and the end of the pipe was about 1m from the pond so it was making a little bit of a splash as it entered. I did notice before sunset a lot of pla tapien were close to the surface and looked as though they could be struggling a bit

[LoeiI]

3 hours ago, kickstart said:

How deep is the well, could the water be sightly Salin, water from a well is different from rain fed, some fish do not like a change of water supply I know Bla Dok, walking catfish, do not like a change of water.

We have a pond and pump water on to the fruit trees a veg in the garden, during the dry season not enough water in the pond so the wife uses mains water from underground supply, some of the fruit trees start not look too well, soon as the rains come, they pick up. 

The Mrs uses the well water for her veg garden, trees and flowers and they all seem ok, she thinks the fish may have a disease mind you the other day she also said they could be having a heart attack because I catch them and then put them back 

[Skipalongcassidy]

Well water can be cold... colder than the pond water by many degrees... fish do not like that change in temperature... it is a shock to them.

[kickstart]

13 hours ago, Skipalongcassidy said:

Well water can be cold... colder than the pond water by many degrees... fish do not like that change in temperature... it is a shock to them.

Can not see that, think about it the volume of water in the pond, then you are adding some more, with say a 2inch pipe over a few hours not a fast rate, that new water will just mix with the pond water, done during the daytime, when the weather is warmer, they will be very little change in water temperature.

Unlikely to be a disease unless you have a very high stocking rate, unlikely? fish are fairly virulent.

[Skipalongcassidy]

Filling Ponds with Well Water Can Kill Fish - AgriLife Today (tamu.edu)

[LoeiI]

14 hours ago, kickstart said:

Can not see that, think about it the volume of water in the pond, then you are adding some more, with say a 2inch pipe over a few hours not a fast rate, that new water will just mix with the pond water, done during the daytime, when the weather is warmer, they will be very little change in water temperature.

Unlikely to be a disease unless you have a very high stocking rate, unlikely? fish are fairly virulent.

I put a sprinkler on the water supply yesterday hoping the aeriation of the water might help but another 30 dead this morning as I said earlier there must be 7 or 8 different species of fish in the pond but all the dead fish (probably over 100 by now) are all pla tapien. I'm at a bit of a loss really as I top the pond up every year with the well water use the same fish food maybe the tapien are just more susceptible to oxygen depletion which other than a species specific disease is all I can think is causing it, the only thing that has changed in the last 4 years is that the fish are obviously a bit bigger.  

[JimTripper]

Fountain is better. Is you sprinkler pulling water from the pond or just spraying water?

[LoeiI]

1 hour ago, JimTripper said:

Fountain is better. Is you sprinkler pulling water from the pond or just spraying water?

Its spraying the well water, the Mrs just spoke to the farmer next door he said the Tapien are more susceptible to oxygen depletion than the other species and for better aeriation to pump the well water in about a meter under the surface so I've got the sexiest pipe fitter in Thailand on with it as we speak  

[JimTripper]

1 hour ago, LoeiI said:

Its spraying the well water, the Mrs just spoke to the farmer next door he said the Tapien are more susceptible to oxygen depletion than the other species and for better aeriation to pump the well water in about a meter under the surface so I've got the sexiest pipe fitter in Thailand on with it as we speak  

I don't think that's really going to increase oxygen levels much but may help a little, you're just pumping new water in.

 

What you need to do is spray water up into the air that is fed by the pond water.

 

Take that sprinkler system that's there, route the inlet pipe to the bottom of the pond, and use a pump to make it operate so it draws the water from the pond and not the well.

 

It's hard to get oxygen to the lower levels of the pond, because oxygen rises, that's why having the water inlet draw from the bottom of the pond works best, it takes that lower level water and adds oxygen when it's sprayed above the surface.