Goldfish Lying At Bottom Of Tank

[FishLover4+1]

Hi, my sisters goldfish has been lying at the bottom of the tank. He'll lie there for a few minutes then swim around for a few minutes then lie down again. I'm not really sure what type of goldfish he / she is, he has a body shaped like a common goldfish but patterns and a double tail like a shubunkin (not sure about the spelling). The tank is 160l but has been just over half full for a few days as it had to be moved away from the wall for the decorator. I don't have a test kit but my sister is doing a water change of about 30% of the current volume then is filling it up to 3/4 of the full volume. So basically does anyone have any idea what is wrong with the fish and what we can do to help it? Thanks

 

[LyraGuppi]

Perhaps ammonia poisoning?
 
Try doing a water change and then fill it up to it's full volume.

 

[fluttermoth]

Without any test results, it's hard to be positive, but I would suspect a water quality issue of some sort; that's the answer in something like 90% of fishy problems.
 
Has the filter been running while the tank's been half empty?
 
I would concur with Lrya; get as big a water change as possible done, fill the tank up as much as possible, and check the filter's running.

 

[star4]

If decorating has been done, was the tank covered? paint fumes etc can affect tank water. As already suggested do a very large water change.

 

[fluttermoth]

If decorating has been done, was the tank covered? paint fumes etc can affect tank water. As already suggested do a very large water change.

 
Oooh, good thinking!
 
If you can add some carbon to the filter (but only if you can add it without removing more than  a quarter of the media), then that might help absorb any 'nasties' that have got into the water, as well as the big water change.

 

[Munroco]

It could well be swim bladder disease. When this happens a fish will often lose buoyancy, meaning it has to keep swimming to stay off of the bottom. If it looks healthy otherwise, I'd say this is the problem.

 

[mark4785]

The fish could have ammonia poisoning or a bacterial infection of the swim bladder. The latter can cause a fish to lose balance and it will generally go in the direction of the current.

 

[PakisGoldfish]

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