Hi guys Im new here but i see that most of you are experienced so you may beable to help I bought 4 new koi 3 weeks ago (3 inches) and ive lost 3 of them but put that down to the fact that they were cheap and small then i wake up one morning and one of my large goldfish which was very bloated was dead on the bottom. i put this down to it having something wrong with it due to its bloatedness Yesterday i spent most of the day watching my fish swim and eat happily and also my new sterlet. I went inside to eat my tea came out and there was one of my sarasa comets dead on the bottom in the same place as the goldfish died???? Ive checked water quaility and all is fine i have a pond of 8ftx6ftxd4ft with waterfall and large 5 chamber filter with uv could it be the wheather?? i cant face loosing any more
I don't have a pond yet hopefully soon, but it is always advisable to quarentine any fish to be added to our establised tanks/pond because the fish you have will already have built up a resistance to any nasties in the water where as the new fish will not have, also the new fish may have things that your established fish have not built up a resitance too so may catch a disease
the testing kit i use is tetra ph was8.0 ammonia was 0.0 Ideal and so was the nitrate i inspected the fish very carefully the gold fish was very bloated but the sarasa comet looked fine no marks atall??? I have put a big umbrella up today incase its the wheather but ive gad the fish for years and ive never lost one due to hot wheather before
Two issue here. One is the lack of quarantine which has been covered so I won't labour the point other than to say never trust anyone.
The second issue is more unique to a pond and hot weather. How many plants do you have in the pond? Is it full of algae? I don't mean just green water but string algaes, algaes on the wall, etc.
How much aeration do you have? Waterfall, spray bars, airstones, venturi device?
What can happen in very hot days, the saturation point of dissolved oxygen in the water is naturally lower. During the day, the plants release oxygen so it is under control but after sunset, the plants start releasing carbon dioxide and absorbing oxygen instead. This have the double whammy effect of dropping the already low DO2 level and increase the CO2 level at the same time. Larger fish can die quickly and it is put down to mystery fish kills.
The only way to stop that is to increase artifical aeration to compensate.