Guppies Keep Dying

Question
Hello,

I have just started a new freshwater aquarium. I have a heater (set to 24 degrees, confirmed by 2 thermometers), filter (with air pump) and its about 12 litres.

I let the tank cycle for a few days and had my water tested which came back perfect. I put in 2 guppies after letting their bag adjust to water etc and they were perfectly happy and ate fine. The next day they stopped swimming around and sat near the surface of the water as if gasping for air - despite the fact that the entire surface is covered with bubbles from the pump filter. They both stopped eating and died over the next two days.

I added a little aquarium salt as the pet shop advised their current water has it and then bought another guppy who is now going through the same symptoms

- swimming and eating fine (not over feeding)
- slowing down
- just sitting at surface in one position
- not eating

I have had my water tested again and it came back perfect. I even add a little Stability each day for new tank syndrome.

Please help, I don't want another to die.

Thank you very much,
Chloe

Answer
Chloe,
Unfortunately, most large chain pet store do not know much about the fish they sell. Had they known about fish they would have told you a tank cannot and does not cycle in a few days. It take 3 to 6 weeks to cycle. If you had the water tested in the first 2 days, it would come back good because the cycle process had not started yet. Your guppies are suffering from ammonia and nitrite poisoning. Here is how you cycle a tank:

You add the gravel, after it has been rinsed in hot water, heater, if a tropical tank, filter, thermometer, and any decorations you will have in the tank. Add the conditioned water, turn on the heater and set it to the temperature for the fish you will be keeping, and turn on the filter. Let it run for 1 week. You will see the water start to get cloudy, that is normal. After it has been running for a week, you then "seed" the tank. Seeding is done by feeding the tank fish food. As the food starts to rot, it lets out the ammonia needed in the cycle process. You will do this for about a week. Between the first and second week the first of two bacteria blooms begins. This is the bad stuff. The filter need this to set up. A week to two week later the second bloom sets in. This is the good stuff. Four weeks into the cycle, you will see the tank starting to clear up nicely. This is when you start testing the water daily. Just saying the water is perfect is not correct. You need to know what the ammonia, nitrite, and nitrate levels are in the tank. If after 5 days in a row both the ammonia and nitrites are at zero, the tank has cycled and you can start adding fish. If at any time during the 5 days you get an ammonia spike, you then do a 50% water change and start the testing all over. This means you starts testing for 5 days in a row all over again. This is why the cycle process can take 6 weeks to complete.

Now another problem. 12 liters (3.2 gallons) is not big enough for guppies. The only fish that can be in that small of a tank is a Betta. If you want to have guppies, the smallest tank you can have is 10 gallons and that is just for 2 alone. If you want 4 guppies, you will need a 20 gallon tank.