Golffish

Question
Hi

My daughter has a brand new 10L aquarium with a pump.
We added aqua safe to the water (1 tea spoon)

We bought only two fancy goldfish.Both died within a week.
Firstly swimming at bottom and then floating head down-still alive
for some time.

Can they be over fed...we instructed her only to feed once a day.
What seems to be the problem?

Thank you for your advise!

Answer
Liz,
10 liters is not big enough for a fancy goldfish. 1 goldfish needs a minimum of 20 gallons and 10 gallons per added fish. For example, to house the 2 goldfish you have, they would need a minimum tank size of 30 gallons, or 113.5 liters. Gold fish, even the fancy ones, can get quite large and need a lot of swimming space. They are also huge waste producers so the filter has to be larger than the tank. So, for a 10L tank you should have a filter for a 15-20 liter tank. I believe that fish died because the tank was not cycled. When a tank is first set up, the filter has to go through 2 bacteria blooms. In the first week a tank is set up, the water will start to get cloudy. The first bacteria bloom is the bad stuff that can kill a fish. The second bloom is the good stuff that the filter, gravel and fish need to stay healthy. The cycle process can take up to 6 weeks. I would get a larger home if you intend on keeping goldfish and set it up.

How to cycle a tank with NO fish:

Rinse everything going into the tank including the gravel, filter, tank, and any decorations going in. If the tank will be tropical you will need to add a heater during the set up. Since you have goldfish, no heater is required. Then you put everything into the tank including the water. You will also need to add the conditioner at this time. Plug in the filter, and heater if required and let it run. During the first week, as I mentioned above, you will see the water start to cloud. This is normal and you do not need to do anything to change that. During the second week, the first bacteria bloom starts. This is the bad stuff. Again, you do not need to do anything to the water to make the bloom go away. At this time you will start to "seed" the tank. You do this by feeding it. Everyday, you will add some fish food to the water. As it rots, it will release the much needed ammonia. Again, you do not need to do anything to the water. You will only have to feed the tank a couple of times. In the next week or so, the second bacteria bloom will set in. This is the good stuff. Let the tank go for about a week or so and then you will start to test the water for ammonia, nitrites, and nitrates. Make sure you test the water with a liquid test kit and not the test strips. They are not reliable. So, you will test the water 5 days in a row. If, during these 5 days, your ammonia and nitrites are more than zero, you will do a 25% water change. What you are trying to achieve is 5 days in a row that both the ammonia and nitrite levels are both zero. If during the 5 days, you do get a reading, the 5 days in a row start over. For example. If you test Monday and all is good, you do not need to do the water change. If on Wednesday, you do get a reading, do the water change and start your 5 days all over. If you get no reading for ammonia and nitrites all 5 days, the tank is cycled and ready for fish. Do not add more that three fish at a time. This gives the filter time to accommodate fish into the tank. If you stock it completely, the filter will get overloaded and will not be able to remove any ammonia from the water. Even though the tank has a filter, you will still need to do weekly water changes. You will test the water once a week. The ammonia and/or nitrite levels with determine how much water is removed. If the readings are at zero for both, you will only have to remove 25% of the water replacing it with clean conditioned water. If you get readings for both, then the water change will be larger. Try not to remove more than 50% of the water at any given time. If you remove more, it will cause the fish to get stressed.

Goldfish do not have a stomach so everything they eat comes right back out as waste. Only feed them once a day and only enough food that they can eat in 2 minutes. Any uneaten food should be removed after 2 minutes. With goldfish, you will most likely not have to remove any because they will eat anything put into the tank.