Hi
I've got a largish pond (20ftby 10ft) and max 2.5 ft deep. its got lots of marginals and plenty of oxygenating plants (elodea), also a large waterlily.
I've about 20 fish (goldfish, shubunkins ans a few golden orfe)which I've put in over the last three years, none larger than 5 inches.
in the last two weeks I've lost about 5 fish. they don't have any obvious signs of disease.
Any ideas?