New Tank Syndrome: How to "Cycle" Your Aquarium Without Killing Fish
You bought a sparkling new tank, filled it with water, and added some beautiful fish. A few days later, the water is cloudy and your fish are gasping or dying. This is called New Tank Syndrome.
The Problem: Invisible Toxins in Your Fish Tank
New aquariums are sterile environments. They lack the microscopic life needed to process waste. When fish release waste (ammonia), it builds up rapidly because there is nothing there to clean it up. Ammonia is highly toxic and burns fish gills even in small amounts.
The Solution: The Nitrogen Cycle
To make the water safe, you need to grow colonies of beneficial bacteria. This process is called "Cycling." Here is the 3-step lifecycle:
1. Ammonia (Toxic 💀)
Fish waste and uneaten food break down into Ammonia. This is the first spike in a new tank.
2. Nitrite (Still Toxic ⚠️)
A specific type of bacteria eats Ammonia and turns it into Nitrite. Unfortunately, Nitrite is also toxic to fish.
3. Nitrate (Safe ✅)
Finally, a second type of bacteria eats the Nitrite and converts it into Nitrate. Nitrate is relatively harmless in low levels and is removed by your weekly water changes.
Your beneficial bacteria mostly live inside your filter media, which is why choosing the right filter from our Filter Comparison Guide is critical.
Ready for Fish?
Once your tank is completely cycled (meaning Ammonia and Nitrite are consistently 0ppm), you can follow our Stocking Guide to add fish safely.
Emergency Safety Net
To keep fish safe during this process (or if you have an accidental spike), use a water conditioner like Seachem Prime that detoxifies ammonia for up to 48 hours.
Get Seachem Prime on Amazon