Issues With Deaths in Pond

[rebelliondog206]

I have recently had a few deaths in my 400 gallon above ground pond....the 3 biggest goldfish. All the fish seem a little sluggish today.

I tested the water and it is ok..... .25 ammonia, 5 nitrates. I attributed the ammonia to the dead fish I netted out today? I also cleaned the filter today. I will try again tomorrow. Weekend is cleaning time.....25% water change is usual.....I just water plants with the pond water and then replace it.

Plants are growing like crazy...lillies, parrot feather, corkscrew, and others.

The concern is.....all of the fish have looked / acted healthy till the last week. I have done nothing differently this year.....except:

I have killifish in the pond that I received earlier this year from another member......5 have turned into about 100 at this point.

Do these fish ever act aggressively. I have noticed at feeding time they get right in there and do kinda push the others out. The killies are much smaller but outnumber the others about 5 to 1.

And.....the water gets up to about 90 these days with the weather outside. I use an air pump and have just started having issues with the pond.

Any ideas??

[utsadude]

My guess is heat. Killifish aren't to be worried about I wouldn't believe. I think the ammonia levels can be given to the dead fish in the tank.

[cichlidomaha]

I would agree on the heat anything over 80 and goldfish do not do well.I would add extra oxygen when the water gets that warm. Try doing larger water changes up to 50% if possible. Good luck! Do not feed but once or twice a week in an outside pond. They get plenty of food with algae and bugs in the water.

Tom

[ddaquaria]

My money says heat also. My koi are sluggish right now due to the heat as soon as the shade comes out and it is cooler they are excited for food. I noticed the tropheus are along the edges more while it is hot but the koi stay in the 4 foot deep area. Deeper is cooler.

[rebelliondog206]

Thanks for the suggestions.

I will move the aerator inside....pond is just outside the back window of the house. Blowing cooler air into the water has helped with the temp in the past.

I will also reduce feeding. I have always fed twice a day except over the winter. Of course, they have plants, roots, etc. to eat.