Help ! Several Koi have died in the last few days

[jmt359]

Hi everyone

I have a 3000 gallon spring fed pond with about 50 fish from 3" to 12". The pond is about 3 years old and recently I started loosing about 2-3 fish a day over the last 4 days. the average size of the koi lost were 6-8". I'm very upset because none of the fish had any signs of stress , ulcers or any visible illness. I just tested my water and the readings were:
GH-120
KH-4
PH-7
NO2-0
NO3-20
AMMONIA- .25
PHOSPHATE.25

I'm in New jersey and we have had rain for the last 3 days and I added some water Hyacinths last week.

Any ideas or suggestions would be greatly appreciated. I don't want to lose any more fish if possible.

Thank you all in advance.

 

[Tula]

I am not an expert, but have a koi pond and read regularly. Your KH is very low, which can lead to your PH dropping....rain could be a factor. I don't feel confident giving you direct advice, but I believe adding baking soda is needed. There are excellent article on this subject and also koi forums.

If indeed your numbers are accurate, you'll need to take action. Hope this helps a little. Keep us posted.

 

[jmt359]

Hi Tula

thank you for your feedback. I did go back and check my numbers and indeed the KH reading was wrong its actually 40 and not 4. I must have forgot the zero. I did add baking soda to increase the ph and kh level. I hope that it is just a water level imbalance from all the rain and runoff.

Thanks again

 

[CometKeith]

hi jmt359. I'm so sorry about your fish. I'm wondering about low O2. Do you have much in the way of water movement? Also if you are finding dead fish in the morning then that is usually a sign of low dissolved oxygen because it always drops at night. I would consider adding some pumps and moving more water around and see if that helps.

 

[Dave 54]

Hi kmt359 so sorry about your koi , I wonder the same as Comet Kieth has your pond developed low 02 add extra airstones to the pond
You could try making ph pills made from Plaster of Paris and add thenm to the pond .
It is most distressing when your loosing fish , did you remember to give your pond and filter a spruce up after the winter months to ready yourself for the summer period ?

Dave

 

[MitchM]

You said it's a spring fed pond and you've had rain lately.

How much flow are you getting from the spring?
Does the pond receive water from ground run off?
Could you post a picture?

 

[sissy]

Could something be washing into the spring fed water .That happened to my dad 's pond when I was a kid .Heavy rains and nutrients washed into the pond and he had to divert the spring fed water to the gardens with a ditch we dug .It was just a combo of what was coming from the spring and all my dad's farm .The pond was raised 2 ft above gardens and only place that was lower was the spring water .

 

[jmt359]

hi jmt359. I'm so sorry about your fish. I'm wondering about low O2. Do you have much in the way of water movement? Also if you are finding dead fish in the morning then that is usually a sign of low dissolved oxygen because it always drops at night. I would consider adding some pumps and moving more water around and see if that helps.

Hi Keith thanks for your suggestions. I have a Laguna water jet 2400 pump that feeds the bio filter and waterfall and I also have the fountain spray going to create more O2.
Since I added the ph up last night I didn't find any dead fish this morning. Hopefully that was it. It also stopped raining finally.

 

[jmt359]

Could something be washing into the spring fed water .That happened to my dad 's pond when I was a kid .Heavy rains and nutrients washed into the pond and he had to divert the spring fed water to the gardens with a ditch we dug .It was just a combo of what was coming from the spring and all my dad's farm .The pond was raised 2 ft above gardens and only place that was lower was the spring water .

 

[jmt359]

Hi Sissy

Thank you for the advice. That was what I was thinking as well because all the rain we had over the last 3 days.

 

[jmt359]

Hi Mitch

Before the rain it was down to a trickle after the rain it running about 1 gallon every 2 minutes and that may include runnoff as well.
I attached a couple of pics so you can get an idea below.

Thanks again


QUOTE="MitchM, post: 271831, member: 4402"]You said it's a spring fed pond and you've had rain lately.

How much flow are you getting from the spring?
Does the pond receive water from ground run off?
Could you post a picture?[/QUOTE]

 

[rodsboys]

These are the readings that concern me:
NO2-0
AMMONIA- .25

Any amount of those 2 is toxic. Especially to koi and especially if your readings were 0 prior to the rain. The sudden shock of the toxins added to the water and basically causing a mini cycle could be what did in your koi.

 

[MitchM]

The timing of the rain and the death of the fish seem like too much of a coincidence.
I suspect that surface run-off had something to do with it but it looks like your pond is designed as a catch basin for the run-off.
I'm not sure what you can do about that other than somehow divert the run-off around your pond.
The spring should flush out the existing water on it's own. Do you have any way to test the water from the spring, or is it a spring that feeds the pond from the bottom, in which case you wouldn't be able to get a water sample.