Goldfish Have Disappeared!

by Barbara
(London UK)

I have had 3 goldfish in my small garden pond for about 7 years.

The pond has a well balanced ecosystem, with marginals and pond plants, including water lilies and other floaters.

I recently treated half the pond for blanket weed (not for the first time) and since then, the goldfish have disappeared. I am beginning to think they have all died from a disease as I cannot see any sign of them.

If a fox or a cat had got one, I don't think it would have got all three. Any suggestions?
Thank you.

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Grant's Reply

Hi Barbara

By treating for blanket weed I assume you are adding an anti algal chemical to the water. I'm not clear how you can treat only half the pond though unless physically removing the weed.

If you are chemically treating, or just shading off an area, what has happened to the weed?

If the weed hasn't been physically removed, then it will be decaying as it dies off.

What are your water conditions like?

Has the water suddenly become acidic or is there ammonia present (caused by decay). 1 or 2 ppm (parts per million) is enough to cause stress in Goldfish.

If your water conditions are satisfactory, have you removed a hiding area your fish were using? If so they will have to find another safe sanctuary further away from prying eyes.

If they were tame and removing the blanket weed wouldn't have upset them, then they may have been more obvious to predators.

Don't feed for a couple of days, then put a little food in the water. If they don't come up to feed then I would suggest a predator has got them.

Having said that, I can't guess the number of times I have emptied a pond because the fish have disappeared only to find the fish are still there.