Jump to content

Fish dying


Caryl

Recommended Posts

I have just had a lady ring with a problem. She set up a large pond about 4 months ago. It is lined with polythene, 400cm deep and about 30,000 litres. It had about 100 goldfish in it (largest was 8"). Recently they have been dying and she has lost 45 over 3 weeks. Their tails appear to be shredded. If it is finrot, is there some way to treat a pond that size that doesn't include medicating such a large volume of water?

She has tested the pH and nitrites and both are good.

There is a fine layer of pollen on the surface and she wondered if this was causing a problem. Fish are at the surface but not gasping (although that is probably normal at the moment as it is warm and sunny). There is a small fountain at one end and an overflow, so it has had plenty of fresh water into it over the past month thanks to our heavy rainfall.

Sorry about the mix of imperial and metric but it is how she gave them to me 8)

Any ideas please? They are off to Aussie tomorrow and she is concerned about more dying while they are away.

Link to comment
Share on other sites

evrything i've read about fin rot says to improve water qualityy. but you say it has fresh water constantly... the only other thing, were the fish all from the same source? and chucked in the same time or added gradually? Quote from my bible::

Overstocking a pond, esp if its not well established, places great stress on its occupants, and fish may succumb to the usual bacteria thats in the water. Overfeeding is another common envoronmental problem.....etc

Bit of a shame it's happening when theyre going.

Link to comment
Share on other sites

Fin rot is a bacterial infection that often comes after damage which as suggested could have arisen from mating but I have no idea how to treat fish in 30000litres without moving towards bankruptcy. Improved water conditions and treatment with antibiotics is the usual cure---but that is a lot of water. There are a number of bacteria naturally in the soil that can cause disease in goldfish if they multiply to a high level and they also need to be treated with antibiotics. Sorry I can't realy help---you need some input from someone with experience with large ponds.

Link to comment
Share on other sites

I also have a friend who has had her fish dying. She has bred goldies for over 45yrs and recently they have been dying off for no apparent reason. Unfortunately it has also been all her larger breeding stock.

She has 5 ponds, we have done water changes and cleaned the ponds out, it didn't help. She decided to just leave them now and count her losses :(

The only thing we could think of was the neighbour was spraying and it was coming over the 6 foot fence - the only prob with this idea is that the ponds are on different fence lines. Perhaps it is the changeable weather???

Link to comment
Share on other sites

is there a sizeable amount of algae in the pond? just asking cos as im sure you know, but just in case.... algae respire like any other animal at night, using up O2 and creating CO2. thus at night in a body of water with a large amount of plants you can have fish literally choking and dying of asphixia.

also you could look at adding a airstone or some sort of water movement thatll bring the detritus up from teh bottom, as in a large pond like that is could be that aerobic bacteria are sapping the depths of the pond of oxygen, and if that happens you get anaerobic bacteria taking over and producing sulphides that could kill the entire pond overnight if enough was generated. the air stone would just make sure that the aerobic bacteria keep going rather than the anaerobic.

just a couple ideas that im pinching from my aquaculture papers...

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...