Hi All,

We are having a problem with our tank and goldies, any help and advice is appreciated.

We started off with a small tank with 3 Comets, this tank was running successfully for +- 10 months. A month ago we bought a 20 gallon tank and started cycling the tank for 2 weeks.

After the 2 weeks we introduced the Comets and the Amazon Swords we already had. They were doing very well and were on their own in the tank for about a week.

We then introduced 2 Red Fantails and 2 Bristol Shubunkins. The smaller of the Shubunkins looked ill and we transferred it to a hospital tank. The Shubunkin died 2 days later. Since then we have introduced more Comets and Fantail Calicos.

We had 11 fish in the tank and 3 have died in the last 2 weeks. The fish that died were 2 Shubunkins and a Fantail Calico. The symptoms displayed were lethargy and the fish were swimming lopsided.

The fish would then just lie at the bottom of the tank barely moving and a day or 2 later would die. Now the remainder of the fish are lethargic and lying at the bottom of the tank. It appears that the one large Comet has developed a red ulcer on the side of its mouth. It is still eating normally and swimming around like usual.

We have done a 50% water change and medicated with Tetra GeneralTonic. We have also added a second box filter with activated carbon in addition to the box filter and the undergravel filter already in the tank.

There are 5 Amazon Swords in tank at the moment.


Any advice would be appreciated.

Thank you

Christelle and Ian

With 11 fish in a 20 gallon tank, you were probably experiencing major water toxicity. Generally the rule of thumb is one goldfish per 10 gallons.

To better diagnose your fish, please answer the following
If there are any questions you cannot answer, simply say "I don't know"

• Test Results for the Following:
  Ammonia Level?
  Nitrite Level?
  Nitrate level?
  Ph Level, (If possible,KH and GH and chloramines)?
  Ph Level (KH/GH) out of the Tap?
  Brand of test-kit used? (strips or drops?)
• Tank size (How many Gals) and How long has it been running?
• What is the name and size of the filter/s?
• How often do you change the water and how much?
  
• How many fish in the tank and their size?
• What kind of water additives or conditioners?
• Any medications added to the tank?
• Add any new fish to the tank?
• What do you feed your fish?
• Any unusual findings on the fish such as
  "grains of salt",
  bloody streaks, frayed fins or fungus?
• Any unusual behavior like staying at the bottom, not eating,ect..?

Check out the links in my signature for more details about caring for goldfish.

Nenn is 100% correct. You are horribly overstocked in a 20 gallon tank.

You need to split your fish up and fast. If you don't have another aquarium, many posters here have used Rubbermaid tote containers for emergency situations.

Also, aren't Amazon Swords tropical fish? Trops and goldies do not mix as both fish have very different needs as far as water temps and food.

At the very least you need to do a 100% water change, temperature and ph matched.

Let us know when you have obtained testers or had your water tested at the lfs. If they test it, make sure they give you the numbers, not just that its ok or not ok.

Please answer the questions Nenn posted for you so we can all try to help you save your fish.

thanks for the very quick reply.

Just to check my maths, the tank is a 100 liter tank (90cm x 32cm x 37cm).

When we first setup the tank we treated the water with tetra aqua safe and easy balance. and then we left the tank and filters running for two weeks (we transfered filter media from the old tank to the new one to get the bacteria started).

The fish average in size between 1 inch and 3 inches.

We are in South Africa.

we are using sera dipsticks for testing.

NO3 25mg/l
NO2 5mg/l
GH>10 d
KH 6 d
ph 7.2

No Heater

Aeartion: 2 airstones + under gravel filters airstone

Water change 20% every week

tank size: 90cm x 32cm x 37cm

the tank has been running for about 5 weeks

filtration: 2 X corner box filters with activated carbon and filter floss
1x under gravel filer with one lift pipe.

tetra easy balance is added every time we do a water change.

we feed everyday once with flakes

we have 5 amazon swords, these are leafy plants

Unusual findings on the Goldfish:
one has a ulcer by its mouth

Unusual behavior:
lethargic, some are swimming lopsided and sideways, lying on the bottom


Medications/what has been tried or done do far:
Tetra General tonic, only put in today so nothing we can see.

thanks again for the help

NO2 at 5 mg/L is dangerously high. You want to try to get those down to .25 or below.

Information from GoldfishConnection that I think is pertinent to your situation:


Large and frequent water changes are necessary as well as placing the fish in containers that can hold at least 10 gallons per fish.

All excellent advice for you to follow.

I would add two more things:

a)Do your self a favour and get some dropper testers - strips are very unreliable and you also do not have anything to test for ammonia; this is likely to be very high, also.
b)Test water daily and make large water changes accordingly. 20% weekly will not even begin to relieve the toxicity - aim for 80% daily.

As the others have explained you are suffering from New Tank Syndrome (toxic ammonia and nitrite) and the situation is made worse by being wildly overstocked.

Unless you can afford larger space (or have access to a pond) you might consider returning some fish to the fish store.
Space required for each Fancy = 10g; Comet/common =20g.

The Amazon Swords are leafy plants?!
So sorry, there! I assumed you meant swordFISH, lol!

But on the serious side, your fish are in a very desperate situation. A 20% wc weekly is not going to cut it. Please read about the nitrogen cycle and what it means to your fish on the links at the bottom of their posts above. Water for your fish is the same as air to us. Imagine living in a closet with 6 other people where you cannot leave and someone just gives you food through the door. Maybe thats a little extreme, but I think its a fair analogy.

I noticed that your 2 box filters got carbon in them. When medicating, you HAVE to remove the carbon from your filter because as it will render the medication completely useless.

Having said that, and as the other posters have been saying, the root of your problem is the toxic water in your tank. Get this under control first.

Everyone has already given you great advice. I just wanted to say and let you know that you are doing the right thing by coming here!

A lot of the advice may seem overwhelming, but almost all of us have gone through similar situations before we learned how to take proper care of our fish. Don't feel bad; just try to do the best for your fish.

Good luck!

Setiseeker, how are things now - any improvements?