Bloated Koi And Hanging Near The Surface.

[Duck and Dive]

I visited my cousins house today and had a look at his pond. I noticed a koi hanging with its head in the weed at the surface and is very bloated. They haven't had the filter on all winter so I think that might be one of the problems because it aeriates the pond as well. If you have any ideas what the problem is or what disease it may have could you please post. In the pond there are:

3 koi
1 tench


they are in a 2154 gallon pond with a filter.

Please help!

D&D

 

[Tokis-Phoenix]

If the koi looks very bloated as in it looks like its body is filling up with fluid then its likely that the koi has dropsy- but it is also possible the koi simply has constipation. Did your cousin feed the koi at all over the winter period (particularly when the pond was at 10degree's C or colder) and if so what did he feed the koi and how much/often? Your cousin also needs to test the water quality of the pond for ammonia, nitrites, nitrates and ph with some accurate water quality test kits (you should be able to get them at any decent local fish store), posting the results here on the forum will be very useful as undesirable water quality can make fish ill and such problems are not uncommon at this time of year particularly if the filter has recently just been turned back on .