Goldfish dying

[NickyRich]

Hi there, when my dad passed away 4 years ago, he entrusted me with looking after his pond and his beloved fish. Over 4 years, I only lost 2 goldfish. I clean the filters 3 times a year, it has a metal grid (big holes) to protect from cats and the heron and the fish have been happy. The pond probably contains about 400 gallons of water-it has a deeper 'barrel' type of section and a more shallow area. (I'm rubbish at dimensions). Over Christmas, we lost 5 fish-all of them have been found dead at the bottom of the pond. I did an emergency filter clean, changed 20% of the water, took the water to a garden centre to be tested (all was within normal levels) and put a pond 'bomb' in there along with some pond weed. All has been going well but then yesterday, found another 4 fish. The pond is at my mum's house but she checks the fish every day. The water is completely clear, all the dead fish are staying at the bottom of the pond which I've found odd as when I've found dead fish in the past, I've found them floating on the top. There are a selection of goldfish and 4 orphs. We now have 11 fish left and I'm at a loss why they are dying suddenly. I'm an emotional wreck because I promised my dad I'd look after them and we've lost 9 in the past month! I live in South Wales, although it's cold at the moment, the pond hasn't frozen at all. Please, any advice about what I can do???

Forgot to say, the fish that have been taken from the pond are in perfect condition, apart from the fact they are dead!

 

[sissy]

Do you know how old the fish were .Also do you test the water,also do you have an aerator.It was also over stocked and ammonia could have killed them

 

[sissy]

Normal may not be normal ,did the tell you what each level was .Putting in chemicals to control any weed is never good .Those products always deplete oxygen .

 

[NickyRich]

I may be wrong on the water volume my husband reckons it's far more water in there than that! He thinks it's closer to 650 gallons. The youngest fish is about 8 years old I think. We have a filter system and a pump going. The pond has worked perfectly (as in has kept the fish healthy) for 35 years, including the last 4 years since I've taken over. I think it's odd that we've found all the dead fish on the bottom of the pond but that may well be my lack of experience. We lost our smaller goldfish (between 5-7 inches long) over xmas but we've lost three larger ones today (about 10 inches).

 

[NickyRich]

Normal may not be normal ,did the tell you what each level was .Putting in chemicals to control any weed is never good .Those products always deplete oxygen .

No chemicals have been put in to control weed, sorry, I meant I added some plants. There is a lily in there already but no other plants.
Ammonia was 0.3 and they said the ph was perfect?

 

[sissy]

Ammonia may be only that high if you put in water before you took water to be tested .I would get a test kit and do it myself .Not sure what they tested for either .Ph is normal did they tell you a number .What were all the other tests they did .400 gallons cannot handle many fish and as they get bigger it gets worse for them .If all the larger ones are the ones that died then more will die if you do not get rid of the ammonia .Zeolite works for that

 

[NickyRich]

Thank you Sissy, I'll have a look to get some Zeolite and a testing kit. It's mainly the smaller fish that have died so far. Fingers crossed I can sort it!