Hi

I was looking for some advice as over the last 9 months I have lost 3 fancy goldfish and all to fairly similar symptoms, with the most recent passing away today.

The symptoms are all the same in so far as the fish starts being very lethargic, sitting in the bottom corner of the tank, then progressing to being unable to swim properly / lying on side, etc ... before eventually dying. With the first two this took 10+ days to progress, with my last it all happened in a matter of days. With each the scales seem to puff up (hence why I am assuming dropsy).

Each episode has been 3 or so months apart and the tank gets regular (2 weekly) water changes along with one of the carbon filters. There are no other major changes to the tank environment. I also check the water quality regularly and it always seems to be fine from an ammonia, nitrates and nitrites perspective.

The tank is 200l capacity and had just the 4 fish in. The fish were 3 to 4 years old (which I believe is not particularly old for gold fish if kept well).

We have one final fancy all alone in the tank and I am keen to keep it as healthy and happy as possible. Any thoughts on what I should do differently or is it just "one of those things" that you cannot really do anything about? Should I be changing the gravel at all / ever? It gets vac'ed with the siphon each time but otherwise not replaced.

Photo of the tank attached for ref.

Thanks for any thoughts
S

Would you post actual test results please for ammonia, nitrite, nitrate and pH. Also, is your water hard or soft and what do you feed them?

Hi Fishlady

Sorry for the delay, work is mad at the moment!

I have attached a photo for the test results, my estimate would be:

Ammonia < 0.5 mg/l
pH ~7.6
Nitrate ~25 -50 mg/l
Nitrite ~ 0 - 0.5 mg/l

However I may be wrong, these strips are not the easiest to read! I did take a sample of water to my local aquatic center when Fish 2 started looking ill and they tested it without raising any concerns.

We live in a hard water area and I have not sought to treat the water in the tank (I had read this was not necessary for goldfish).

They get fed mainly on flakes, but sometimes switch to sinking pellets too for a bit of variety.

Thanks
S

Hi

Test strips aren't terribly accurate, but from what I can see it looks like you have .5 nitrite and 100 nitrate (it's the shade of colour rather than its strength). I strongly suggest you use a liquid based test like this one for more accurate results.

If the results I'm seeing are correct, the issue is partially the nitrite which should be at 0 and also the nitrate which as goldfish are very sensitive to it should be below 20ppm. The pH and hardness are fine.

You need to do a number of water changes to get nitrite down to 0 and nitrate below 20ppm. Treat the water with a dechlorinator which is essential for all aquariums as the chlorine/chloramine in the supply kills bacteria, including the beneficial bacteria in your filter. I suggest using Seachem Prime for this as it detoxifies ammonia, nitrite and nitrate while you're taking action to permanently reduce them and is also much more economical than most others. Ongoing, a 25% minimum water change is necessary every week (and possibly more depending on how fast nitrate rises) to maintain a low nitrate level.

Additionally, goldfish are better fed on sinking foods as when they eat flake, the also swallow a lot of air which can cause swim bladder issues and make them inclined to float or to have trouble steering.

Thanks for the advice, that is all very useful.

In relation to the substrate in the tank, does this ever need replacing or is it fine just being vacc'ed? I have had the same gravel in there for 3 years so I may be unwittingly causing grief there too!

Ta
S

There's no need to change the gravel, just syphon the dirt out when doing a water change.

I agree that the water changes should be at least weekly.

The other potential concern I had was you mentioning that "...and the tank gets regular (2 weekly) water changes along with one of the carbon filters". Is this is a filter in which essentially all the filter media (sponge/foam, filter wool, carbon, etc.) are completely replaced every time? If not, and only part of the filter media is replaced, that should be fine. However, if it's all being replaced every time, then essentially the tank would be going through a mini-cycle or even a complete cycling process every time - and this would account for the presence of ammonia and nitrite and higher nitrates than ought to be the case.