I concur with what's been posted. Additionally, what is your water pH? This has a relation to the ammonia's toxicity, which is why i ask.
You will need to make some decisions on the fish, removing some and adding more of some others. You may find our profiles helpful, second tab from the left in the blue bar across the top of the page. In posts if the name is the same as used in the profile it will shade, example Serpae Tetra
and Bala Shark
, and you can click the shaded name for the profile. Please check out the fish that you now have, in order to determine which must go and which species need more.
One note, the Serpae T I would get rid of, they can be nippy and this is problematic for other fish so your choice will be severely limited. A tank of just 12 or so Serpae is one option, but if other fish are wanted they should go.
And welcome to TFK forum.