All the fish died

[leni]

My partners grandparents have had a pond for years (17 yrs) and have a pump to circulate the water down a waterfall but no filter system (no matter how much you tell them to get one they won't)

Last week the last of their fish died (never been a big problem as they've lost maybe 1/2 a year) but they've lost 8 this year.

My partners persuaded them to let him empty the pond completely and clean it up and found 1 ft of sludge at the bottom with what he believed to be - fish bones.

The pond got refilled last week and they were after some koi, my partner feeling guilty went and bought them 3 but I fell in love with them and put them in our own pond and took 4 of our 7 goldfish to his grandparents instead. We bought these goldfish when we first made our pond last year and we eagerly put them in as we were still filling the pond up and they suvived so we know their "hard" little fish.

anyway back to their pond - they have some 30-40 frogs innit and I was wondering whether these, along with no filter system had slowly killed the fish?

cheers in advanced

 

[black angel]

i would say the lack of a filter would have played a big part in it. did they do any water changing in the time they had it, because if they didnt do them or not very often the ammonia would build up.
cant give any more advice though as i'm not sure about ponds and hope someone can help you further

 

[bribones]

a filter is a must for any pond containing fish unless large and heavily planted

plants take up any excess nutrients in the water and help maintain a balance

you havent stated the pond size but 30-40 frogs is quite a heavy load ,things like samonella could be a factor and the fish dying and rotting in the pond wont have helped,what size pump is in the pond ? i ask this to get a rough idea of how often the water is rotated ?bad circulation will lead to the fish suffocating,

im not having a go but often people just dig a hole and fill it and expect things to be ok ,the same rules as keeping fish in a tank apply to a pond but on a larger scale with more external factors to take into account,derbis rainfall weather wildlife etc you have to combat all these with pumps filters UV sterilisers or treatments ,as well as vigilant maintainence/water changes

all these things should be taken into account before even thinking of adding fish to a pond