Hi Prince. It sounds like your tank had not cycled if you're getting ammonia. First things first (if your fish are still with us, if not, to prevent this happening to you again):
Read this article on the nitrogen cycle:
http://www.fishlore.com/Forum/97-aqu...d-first.0.html
Then, get a test kit (not the paper type). Everybody seems to swear by the API kit. Once you have the kit, regularly (2x daily) test your ammonia and nitrite. Daily test your nitrate. As your tank establishes itself, you should have no more nitrates/nitrites, and you should just test the nitrate if you have suspicions that something is not right (e.g. purple gills, gasping for air). For ammonia and nitrite, anything > 0 means your tank has not cycled, or is going through a mini cycle.
Here are the toxicity levels in my experience: ammonia > 0.5 is toxic to your fish. I would not recommend nitrate > 25 or nitrite > 1. If you see anything higher than that, perform a 50% water change. Do condition the water before putting it back in (use Prime). You should always condition tap water, even when not cycling.
Oh, and you're overfeeding your fish (that's why there's flakes left). Their stomach is no bigger than their eye, apparently, so that's a tiny quantity. You must always scoop up uneaten food (or nitrate/nitrite levels may raise).
Do you vaccuum your gravel? If not, please start doing so.
I hope it's not too late. Judging by the date of the post, it may well be.