Dying Goldfish

[Dave C]

Hi Folks. N ew Member here. I am having an issue with my pond. Live in Atlanta GA area. Over that last 2 weeks most of the goldfish (about 24) in my pond have died, but all of my Koi are fine. Water quality is good. Chemicals are all within normal limits. None of the fish have shown any signs of stress, disease or trauma. Pond is netted. No Fertilizers or Pest Control Products have been used anywhere near the pond in well over a year. about 1200 gallons, 10yr/old EPDM liner with sand and rock bottom. 3600gpm pump in a Mechanical/Biological Filter approx. 3/4 of water is pumped to waterfall and 1/4 is used for bottom circulation.

Anyone have an idea as to what would kill the goldfish but leave the koi with no apparent problems?

 

[Lisak1]

I don't know what's killing your goldfish, but I would guess that they are dying first because they are smaller. Your koi may soon follow.

 

[Mmathis]

@Dave C This is a copy/paste from our "Illness & Disease" topic. You have already answered many of these questions, but it would be helpful if you could read through and fill in anything you haven't already told us. I am most interested to know what your total fish load is [number and size of koi AND goldfish], the actual numbers for your water test results, what your local weather [temp] has been lately, and if you've added any new fish.

"Before posting please take a moment to think about what information could really help the other members to help you. If your question is about water quality then this is particularly important! Water quality can have a great impact on fish health. To help us better help you with your fish or water problems please read the following.

The more information you can provide, the easier it will be for any issues to be identified. Therefore please answer these questions as completely as possible:


Water quality
* Ammonia Level (pond)
* Nitrite Level (pond)
* Ammonia Level (tap water)
* Nitrite Level (tap water)
* Ph Level, pond (If possible, KH, GH and chlorine)
* Ph Level, tap water (If possible, KH, GH and chlorine)
* Brand of test-kit used and whether strips or drops?

Other useful information:
* Water temperature?
* Pond size and how long has it been running?
* What is the name and size of the filter(s)?
* How often do you change the water and how much?
* How many days ago was the last water change and how much did you change?
* How many fish in the pond and their type?
* What kind of water additives or conditioners have you used?
* What do you feed your fish and how often?
* Any new fish added to the pond recently?
* Any medications added to the pond?
* List entire medication/treatment history for fish and pond
* Any unusual findings on the fish?
* Any unusual behavior like staying at the bottom, not eating, etc.?

If you do not have a test kit, you may be able to take samples of your pond and tap water to your local fish store for testing (which is often free). Please request [provide] numerical results rather than generalizations like "OK", "fine", "safe", "acceptable", etc. However since knowing your water quality is important, we suggest you get your own test kit. A drop kit is both more accurate and much less expensive per test than the test strips.

Photos can also be a big help!"

 

[Mmathis]

And most important, hello and welcome to our group!

 

[Meyer Jordan]

Quick question: Have you added any new fish lately, especially Goldfish.
You can immediately eliminate any Oxygen issues. Two (2) reasons- Larger fish succumb first under low Oxygen conditions and Goldfish can tolerate much lower Oxygen levels than Koi.
Look forward to any additional information that you can provide.