Question: how to lower the ammonia in a fish tank?
Answer: Water change! The first thing you want to do is perform a water change of at least 50%. ... 
Add cycled filters. ... 
Water conditioner. ... 
Ammonia-removing filter media. ... 
Double check how many fish are in your aquarium. ... 
Overfeeding. ... 
Perform regular maintenance. ... 
Don't kill your beneficial bacteria!