A friends pond and his annual problems...

[nickmcmechan]

Guy I know has a 876 gallon (think thats about 950 US Gal) pond.

Every year some of his goldfish get bloat and die

Apart from that he tells me all is well (paramters)

He uses UV filtration (2 x 8W).

He took a water sample to the Vet who sent it for analysis...they said they thought the local frogs may be bringing bcateria to the pond.

I advised him to run a second UV...

Was mine / the vets advice right?

 

[wataugachicken]

i have a lot more questions:

is there other filtration besides UV?
test for ammonia, nitrite, nitrate?
any water changes for the pond, or a stream that feeds fresh water into it?
how old are the goldfish?
what does he feed them? how much/how often?
if he buys a big bag of food at the beginning of the season, possible that it spoils before he uses it all?
any trees or bushes nearby that drop leaves or fruits into the pond? fruits could cause digestive trouble, leaves could lower pH.
do they just get fat or do they have pineconed scales like dropsy?

 

[nickmcmechan]

dont know all the exact details, but heres what i picked up from the conversations:

biological filtration as well as uv
ammonia and nitrite zero, not sure about nitrates
no water changes, heavily planted
various ages of goldfish
dontknow about feeding
pineconded like dropsy

 

[riddle4sphinx]

This could be a load of crap that I heard once, but worth it to find out i guess.... I heard once that sudden water temperature changes can shock a fish and shut down its kidneys which would cause the symptoms of dropsy. Whats the weather like in Scotland, and is he using a heater in the winter?

 

[teleost]

Sounds like dropsy and I've noticed that overfeeding can either contribute or even possibly cause it.

Just a thought but does this always happen in the fall once the temps cool? If so, it might simply be a case where the fishes metabolism slows due to the cool temps yet your friend continues to feed at the same rate as summer?