New pond, bad results

[tgro719]

Hopefully can get some help. I built a small koi pond three years ago. No problems. Six healthy koi. This summer I expanded the pond (essentially, created a second pond and connected them with a "swim-way" (about 2ft long, 1ft wide, and 1 ft deep). The second pond is larger and deeper than the original (probably 4ft long 3ft wide--at the widest--and 3 ft deep and its deepest). I also added a second waterfall to the new end of the pond. So now there are two waterfall on each end and lots more room. However, since introducing old fish into the expanded pond (then replacing them with new fish), I can't keep the koi alive for more than three days. What's going on?

 

[j.w]

@tgro719
We will need more info. Test results on water quality, size of koi, total size of all ponds, equipment, did you quarantine the new fish first etc. Also did you add any chemicals or do any major cleaning?

 

[tgro719]

Total pond size is about 300 gallons. I have two tetrapond waterfall (the filter boxes) as well as bioballs in the filterboxers. since expanding the pond, never had more than six fish (6" biggest, then newly bought ones 3" or so). But during my last two attempts, only had 3 fish, all 3". yes, quarantined the fish and "bag dropped" them. no chemicals for cleaning. I purchased a new liner and installed it. haven't tested water (but used the same source as when I successfully kept them alive before this summer), but after the first wave of deaths, kept the pump/filter running for almost a week without adding new fish. still didn't work.

 

[mrsclem]

If your pond is truly 300 gallons then that is most likely the problem. Koi are picky about water quality. Get a liquid test kit and post your results. I'm guessing the ammonia is high. Did you use tap water and if so, did you treat it for chlorine?
Post some pictures of the pond and setup, those always help.

 

[SarahT]

Do a test on the water, as it isn't just the source water that can be an issue, ammonia and other levels from the fish poo and decaying plant matter can be the problem. Where are you located; is the weather currently really hot? Hot water holds less oxygen, even though your small fish aren't all that much of an oxygen load (though more quickly than you think, those fish will outgrow your pond and you will need to find them new homes or build a bigger pond.) Is there any water runoff into the pond that might have brought chemicals or pesticides from somewhere else?

 

[Mmathis]

Your pond is too small for koi. Koi produce a lot of waste, which can lead to poor water quality issues if the filtration isn’t adequate to handle this. Are you adding a dechlorinator to your water when you add new water?

You have added more oxygenation with the waterfalls. That’s a positive move, but it won’t solve your problem. Please consider only goldfish until you are able to build a pond larger than 1000 gallons (1000 gallons for the first koi, and 250-500 gallons for each additional koi — they grow fast and big).

Also, get a liquid water test kit and test your water for ammonia, nitrites, nitrates, and pH (KH as well if you can get that kit). Liquid kits are more reliable than test strips. Read up on the nitrogen cycle — this will help you understand better what’s going on with the water.

So sorry you are going through this — we all have bumps in the road, but we learn more from our mistakes than we do our successes. Hang in there!

 

[tgro719]

Thanks everyone! very helpful!!

 

[tgro719]

Update. Tested the water (took water sample to aquarium/pond specialty shop). They are baffled. Ph 7. No Ammonia. Water was a little hard (common to my area, but he said he uses city water in his koi pond with no trouble). attached picture of the pond and one of the water tests (lighting and poor camera phone is distorting the color a bit). Any other ideas?

 

[Lisak1]

While I don't know why your fish keep dying (although all trails seem to lead to a water quality issue or a pond that hasn't cycled, I'm not all that well versed on pond water chemistry), I'd suggest you stop trying with koi - they will get too big very fast for your tiny pond. If the "pond specialty shop" didn't recommend against putting koi in a small pond, I would question their professionalism.

Good luck to you - pond keeping is a relaxing hobby, but it can be stressful when things start to go haywire! Lots of smart friendly folks here who will walk with you through the trials - hang with us!

 

[GBBUDD]

Total pond size is about 300 gallons. I have two tetrapond waterfall (the filter boxes) as well as bioballs in the filterboxers. since expanding the pond, never had more than six fish (6" biggest, then newly bought ones 3" or so). But during my last two attempts, only had 3 fish, all 3". yes, quarantined the fish and "bag dropped" them. no chemicals for cleaning. I purchased a new liner and installed it. haven't tested water (but used the same source as when I successfully kept them alive before this summer), but after the first wave of deaths, kept the pump/filter running for almost a week without adding new fish. still didn't work.

what are you doing for o2? 300 gallons is beyond small for koi and i can see them stripping the water of oxygen very quickly if they are of any size

 

[Lisak1]

I think the OP is adding relatively small fish and they are dying rather quickly.

Also just noticed your test kit says "saltwater ammonia" - not sure if it matters for ammonia or not...

 

[tgro719]

Right--the small, newly bought fish have all died. As I mentioned, I was able to raise three koi to 2-3 years old (the pond was a Covid lockdown project). This summer everything went down hill. The person at the pond shop recommended goldfish and shubunkin. still a little hesitant. i don't want anymore blood on my hands.

 

[rubyduby]

Beautiful "little" pond! Goldfish are your best bet..WAY too small for koi...I have shubunkins and they are just as colorful and beautiful as koi with a LOT less waste! Still, judging from the pics your pond is small and I would not put more that four in there (they multiply REALLY fast if conditions suit them) I started out with three and now I have about thirty

 

[Mgessert]

You could just run it for a while with lots of plants and no fish, then in the spring add two or three goldfish. I started with three in my 300 gallon pond, and now rehome the biggest ones as they multiply.