Dying Goldfish

[JCC]

Hello all,
We are at a loss at this point with an issue we are having with our pond. So, after a google search and finding this forum, I'm reaching out with the hope that someone may be able to help identify the problem.

We've had the pond since last May. We actually took over my wife's mom's fish from her pond. Some of the goldfish are 10+ years old. The pond is 12’ x 11’ x 3 feet deep. We’ve had fish dying for the past two weeks, 5 up to yesterday and now two more have died today. We have 3 fish pineconing. Several are lethargic, staying in one spot not eating or swimming. One fish is very very skinny. Our water parameters are good, We have an API LIQUID TEST KIT. Zero ammonia but also zero nitrates, we're assume because it’s heavily planted. The pond does have an awning over it, gets about four hours of morning sun and is filtered with a bioball filled filter.

We did treat the pond on Monday with Prazi thinking it was flukes. The fish that have died didn't appear to have any physical symptoms but we noticed the 3 pineconing yesterday. These 3 are still alive at this point. My wife noticed this white stringlike substance in the pond today. We do plan on emptying the pond and refilling this weekend and possibly giving the fish a salt bath while they are in the holding tank but they seem to be dying at a faster rate each day. Any advice is greatly appreciated!

 

[JCC]

I forgot to mention that no new fish have been introduced into the pond. The only recent change is we added a couple of aerators several weeks ago.

 

[j.w]

and welcome @JCC
I'm not one to know much about fish diseases but if you drain all that water out of the pond and start all over you may be adding more problems as your water need to cycle all over again. Do you have well water or city chlorinated/chloromine water? If you have city water w/those chems in it and you aren't adding dechlore to get them out then that could be one problem. If you are doing that then that wouldn't be a problem. Hopefully someone w/more knowledge on what is going on will show up soon. Adding meds like that Prazi and not knowing for sure what is wrong will not help. How many fish are in there and how big are they? I see you added aerators and that can't hurt but still if you have very large fish and a lot of them and not very good filtration I'm wondering about oxygen issues. I'm just guessing tho so wait for someone else.
Sorry this is happening and hope you can save the ones that are left.

 

[JCC]

Thanks j.w. It's city water. We added Stress Coat when did the first fill and planned on adding again. Fish count is roughly 20 now. Most are in the 2-3 inch range. There are 2 that are around 5-6 inches. If it helps, I also just remembered we have had some jumping out of the water if that's means anything.

 

[j.w]

Each and every time you add new city water you need to add the chlorine/chloramine remover. If you don't this could kill the fish. Does not sound like you have too many fish. Jumping out sounds like there is a water problem perhaps? Did you put city water in ever w/o the removal stuff?

 

[Tula]

I'm sorry you're losing so many fish. Hopefully you've been adding dechlorination to the city water.

Do you know what your PH and KH values are? A PH crash can cause rapid loss of fish.

In an ideal situation it's best to know what you're treating for when medicating fish. In a situation where that's not possible and you're losing fish at a rapid rate and water parameters ( including PH and KH ) are good, then I personally would try a shotgun treatment approach.......treating with some type of broad spectrum product.

I can't see well enough to determine what the stringlike substance is. Again, I'm very sorry you're going through this.