Thankyou for your reply Ozzy. The lack of oxygen was my first thought because of the warmer weather we were experiencing, however I now understand the problem. I thought if I were to leave half the filter alone( so to have sufficient good bacteria to establish the filter) but wash the other half and with the warm weather the sponges would be dry when I place them back into the filter all would be good. Well even though the water was perfectly clear , upon checking my water chemistry, the water was fish killing water , high in Nitrite and ammonia. Partial water changes done and some good bacteria place into the filter and pond water to establish the eco system back to normal and all is good and healthy.We live and learn.
I have a pond that is very well established, possibly 10yrs plus old. It is about 7ft x 4ft kidley ish shape maybe apx 3ft deep in the middle. I have a mix of Koi and Orfe one tench and some gold fish. I use a 7 stage gravity filter Blagden I think, with a good flow of water ie a sufficient pump. I keep coming home to dead fish so far about 4 big gold fish and one which seemed to be healthy Kio. Two of the gold fish looked a bit fat and struggled to stay away from the surface and they have been this way for a long long time, but all the others seemed to be fine. I have notice a lot of the fish seem to not be to active , ie resting at the bottom of the pond some of the time in the shallows. The water is very clear crystal , ie can see the bottom of the pond. Obviously I am concerned that I may loose some of my bigger specimens , the Koi and the Orfe. Any advice would be appreciated?
Thank you for taking the time to reply, I phoned World of water in Romsey and they had said the same as you. The leaches are very dark with no stripes.I was informed that there is some thing that can be purchased to kill them although the person I spoke to today said they probably will not pose a problem to the fish.
Hi I am hoping I can get some advice,today I was cleaning my pond filter and notice a few, I think leaches in the filter along with loads of what lock like wood lice but slightly different . I would imagine these might be some type of lavia. But my concern is the leaches will thes if they are leaches pose a problem for my fish? Any help will be appreciated.