Dying Goldfish, Pleadse Help

[21rm]

Hey all, Im not a usual to this part of the site, im usually hanging out in the tropics area
but me friend is having problems with his goldfish pond at the min. In the last few weeks, since just after xmas time, many of his goldfish have died.

He has never had a problem like this before and the pond is established for a couple of years.
there are frogs in the pond also but they have never been a problem before. could frogs carry diseases that would killl the fish??

the fish have bred quite readily in the past so the pond was quite suitable for them.
There is no filter in the pond, my friends uses straw as a natural filter.

Im not sure if Ive left enough info here, but if more needed just ask

 

[black angel]

depends on if he does water changes or not..siz of pond and volume of water...how many fish and sizes,,types of...if theres not filter then it may be stagnant

askhim to test for ammonia, nitrites and nitrates...also, a lack of oxygen will kill fish.

 

[21rm]

hey thanks angel. will try that out and get bak to ya