Hello from the tropical Vietnam. I’m sorry admit i’m quite ignorant about pond keeping because although i have a koi pond for 4 years, i’ve mostly never had sick fish, thanks to an undesirable setup. More on that below. That changes today, and i’m suddenly stressed and very worried.
My 13 m3 outdoor hard walled pond in Vietnam is filled with a 2-ft thick sand at the bottom. It has a tiny biological filter, no UV, and a very low circulation pump rate_ I couldn’t do anything to change it. For 4 years, the filter system works very poorly. Pond water was mostly muddy or algae cloudy, with only a few short spans where the water was kinda clear. The ecology of the sand bottom layer didn’t filter the water as i had hoped.
Because I cannot change the filter setting without the huge cost of breaking and rebuilding the pond, I resigned to keep 4 fishes only. Apart from the visibly unclear water, the fishes live ok. I guessed the nitrite, nitrate and problem of overcrowdedness, overfeeding is not applicable here.
Last month, I changed the position of the filter j mats inside the biological filter. Miraculously, the water became very clear. It’s nowhere near the clarity in those black-painted hard bottom ponds with big filter systems as populare here, but this was beyond my expectation. It’s clear, it’s beautiful and looks healthy. I was so happy. About a week before the reshuffling of J Mat, i introduced a new batch of 5ea 20-cm new kois to the pond.
But recently, for about 2 weeks now, my bigger fishes don’t want to eat much any more. They also tend to stay motionless for most of the day. Because my pond is shallow and spread out and the water flow doesn’t create any water current, my fishes were never forced to move much for years. They are shy and usually find quite spots to stay idle. But now they are even more ‘resting’ than before.
Also recently they seem to do more flashing. I liked to think they’re doing it because they’re so happy with the new water clarity. There’re big rocks in the pond, but the fishes only flash at the sand surfaces. But I was wrong. The biggest fish dies this morning. Its belly is soft. I didn’t see anything with the scale or in the gill, but I probably don’t know what to look for.
I’m afraid all the big fishes will follow soon. They were acting similarly. The new and smaller fishes are active moving about and still eat. They went through same water transformation, but still eat well and do move about, though not move very much because there’s no stream or undercurrent in the pond.
pH : 7.5
Could you please look at them and tell me what you think about their health and what I should try. I really hope you could help. Thank you!
Also there was a huuuge rain 10 days ago, first seasonal transition rain, from dry to rainy. It may be relevant?
I’m pumping out 20% water. Test pH at 7.5. Ordering test kit for NH3, NO2, reading a lot and confused more. What should I do next?
My 13 m3 outdoor hard walled pond in Vietnam is filled with a 2-ft thick sand at the bottom. It has a tiny biological filter, no UV, and a very low circulation pump rate_ I couldn’t do anything to change it. For 4 years, the filter system works very poorly. Pond water was mostly muddy or algae cloudy, with only a few short spans where the water was kinda clear. The ecology of the sand bottom layer didn’t filter the water as i had hoped.
Because I cannot change the filter setting without the huge cost of breaking and rebuilding the pond, I resigned to keep 4 fishes only. Apart from the visibly unclear water, the fishes live ok. I guessed the nitrite, nitrate and problem of overcrowdedness, overfeeding is not applicable here.
Last month, I changed the position of the filter j mats inside the biological filter. Miraculously, the water became very clear. It’s nowhere near the clarity in those black-painted hard bottom ponds with big filter systems as populare here, but this was beyond my expectation. It’s clear, it’s beautiful and looks healthy. I was so happy. About a week before the reshuffling of J Mat, i introduced a new batch of 5ea 20-cm new kois to the pond.
But recently, for about 2 weeks now, my bigger fishes don’t want to eat much any more. They also tend to stay motionless for most of the day. Because my pond is shallow and spread out and the water flow doesn’t create any water current, my fishes were never forced to move much for years. They are shy and usually find quite spots to stay idle. But now they are even more ‘resting’ than before.
Also recently they seem to do more flashing. I liked to think they’re doing it because they’re so happy with the new water clarity. There’re big rocks in the pond, but the fishes only flash at the sand surfaces. But I was wrong. The biggest fish dies this morning. Its belly is soft. I didn’t see anything with the scale or in the gill, but I probably don’t know what to look for.
I’m afraid all the big fishes will follow soon. They were acting similarly. The new and smaller fishes are active moving about and still eat. They went through same water transformation, but still eat well and do move about, though not move very much because there’s no stream or undercurrent in the pond.
pH : 7.5
Could you please look at them and tell me what you think about their health and what I should try. I really hope you could help. Thank you!
Also there was a huuuge rain 10 days ago, first seasonal transition rain, from dry to rainy. It may be relevant?
I’m pumping out 20% water. Test pH at 7.5. Ordering test kit for NH3, NO2, reading a lot and confused more. What should I do next?
