Koi Bunching Up

[pcjacob]

Hi and greetings from India
Recently i have noticed that my Koi bunch up at the corner of my pond near the top and look like they are gasping for breath. I hardly see them swim around like regular fish. Could this be due to lack of water movement in my pond? I just have air duffusers to airate the pond and no water pumps. Also their food intake has been considerably low ever since i shifted to Hikari economy pellets. Does a drop in water temperatre due to the rains have something to do with it? Ive been doing partial water changes but still see no improvement and the fish have been like this for over two weeks.
Any help would be highly appreciated.
Thanks
With regards
Philip

[MCA]

Hello Philip and welcome!

You say there are no water pumps...only air stones. What kind of filtration plan do you have for the pond? Other than a mud pond that has extremely low stocking levels, we need filtration systems to handle the conversion of ammonia to nitrite to nitrate. And put push or pull through the filter sytem we need water pumps.

The alkalinity of the water will drop in a closed system. That is because the fish exhall carbon dioxide that becomes weak carbonic acid in the water. Rain water falling through the atmosphere also picks up cabron dioxide and delivers weak carbonic acid to the pond. So the alkalinity in the pond will try to counteract the acids and keep the pH steady. If the alkalinity is used up and not replaced (water changes, adding baking soda, adding limestone or oyster shell) the pH will slide do into the acid range (pH below 7). Eventually the water can get too acidic for the bacteria to convert ammonia-nitrite-nitrate. Then you can have toxic levels of ammonia.

So please tell us more about your pond size and volume, how you do water changes, water parametes (ammonia, nitrite, pH, KH or alkalinity). We will all help as we can from this side.

[pcjacob]

Well im ashamed to say i dont have any filteration system. My pond dimensions are 8ft X 2.5ft X 2ft. its basically a mud pond with the floor actually having mud (earlier used to grow water lillies and lotus in this pond)

But to compernsate for filteration every 5 days i change about 25% of the water either by physical removal and replacement of water or by letting the pond over flow for half and hr with fresh well water.

For the past 2 years this system worked well which is why i didnt invest in a filteration system. Of course my 8 Koi have grown to about 10-12 inches in these 2 years and maybe their bio load has gone up by geometric proportions.

Just before heading out for work today i have put 6 activated carbon sachets into the pond just so that some amount of ammonia and such maybe be absorbed from the water.

regards

Philip

[JasPR]

This is really not a good way to keep koi. But if this is your only alternative then increase the frequency of your water changes (25%) to at least twice a week. I would also suggest that now that your fish have grown, it is time to reduce the overall number so that you bring the TOTAL biomass back to a level it once existed at when you had no problems. So find a home for three or four of the largest ones. Best of luck, JR