How to Cycle a New Aquarium

A new fish tank lacks the bacteria to form a steady biological cycle. That cycle proceeds as follows: Fish create the waste product ammonia, which is poisonous to them. Bacteria in the tank change that ammonia to nitrite, which is also toxic. Other bacteria break down the nitrite into nitrate, which is not toxic to fish. These steps will help you to cycle your aquarium on your own.

Difficulty: Easy

Instructions

1. Ask at the fish store if you need special conditioners, since they will be familiar with the composition of the local water. Tap water generally has chemicals in it that aren't good for tropical fish.

2. Fill your tank with water, leaving about an inch at the top.

3. Start the filter system.

4. Add the heater and thermometer.

5. Let everything run for at least 72 hours and get the temperature settings right and the water moving. Freshwater tropical fish do best at 76 to 79 degrees F; cold-water fish prefer a range between 50 and 70 degrees F; marine fish thrive between 75 and 80 degrees F.

6. Put 2 or 3 mollies in the tank. Float each fish in its bag in the tank for 30 minutes to bring the bag water to the same temperature as the tank.

7. Add 1/4 cup of tank water to the bag and retie it.

8. Do this twice more, removing water if the bag gets too full. Throw that water out - don't dump it into the tank.

9. Take the bag out of the tank and open it.

10. Catch the fish with a net and put it in the tank. Discard the bag water - it shouldn't be added to the tank.

11. Be sure not to overfeed them or you'll prolong the cycling process since fish make waste.

12. Use a test kit after 5 days to check the pH, salinity, ammonia, nitrite and nitrate levels. If they're acceptable, the tank is ready for your fish. If the levels are too high, test it after 4 more days.

13. When the chemical levels are all okay and the tank temperature is within tolerances, it's time to buy your fish!

Tips & Warnings

• Premix the saltwater, if you're setting up a marine tank. This gives the salt time to completely dissolve and allows the chemicals to stabilize. Fill a large bucket with clean, dechlorinated water and use a hydrometer to get a specific gravity of between 1.020 and 1.023.

[Hawaii]

on 6/17/2007 It's been about 3 weeks now since I started my first salt water fish tank. All the walls of the fish tank and the gravel/coral are turning black w/ algea.
What can I do ?

[walkerrt]

on 1/7/2007 Sure fire aquarium kick start.....
1. Great adive in the this article only like live plants both because I like the looks and the fact that they thrive on ammonia and such that fish dont like and help remove it from the water.
2. Then and only then ask a friend or find a find a friendly doctors office with an aquarium and ask for the waste water from a water change. Do this to soon and it wont work, the clorine will kill the bacteria. BAMMM instant cycling. Add fish, watch the levels and enjoy. This is how the pros start tanks they maintain for a fee.

on 6/30/2006 It takes a while for the ammonia eating bacteria to grow and then they change ammonia to nitrite. Then it takes time for the nitrite bacteria to grow and they change the waste to nitrate. If you don't have a large enough colony of bacteria then your fish could die from all the ammonia and nitrite building up. This process takes anywhere from 3 weeks to 2 months. Don't expect to be done cycling your tank in 5 days.

on 2/25/2006 You have to wait more than 72 hours before adding fish. It is very inhumane to cycle a tank with fish, because the fish will be extremely stressed and will most likely die (unless they are a very hardy species) with all the poison in the water. Wait at least 2 weeks, putting a pinch of flake in every day to feed the bacteria that are developing.

on 12/19/2005 A process called Fishless Cycling uses artificially added ammonia to get the cycle going without exposing your starter fish to toxic chemicals.

The process is a bit beyond the scope of this note, but Google will provided a multitude of articles with a simple search.