Hi there,
Something I can't see anyone mentioning so far is that you should also test your tap water for nitrates.
If your tank nitrate is higher than your tap nitrate thats actually a good thing at this point as it means some ammonia has changed through nitrite into nitrate (I'm assuming you've read the cycling pinned posts by now) and in combo with your nitrite reading means the cycle has at least started and everything might yet turn out ok...
If the tap==the tank then in all probability all the waste is still in the tank as ammonia - i.e bad
Even overstocked as you are (it looks fine now btw as 'overstock' is based on adult sizes and you probably have baby fish) your tank will be fine until ammonia builds up to 1,2,3,4,5+ ppm ammonia and then suddenly it all goes downhill

The fish start to shimmy and shake, scratch themselves on rocks, unexplained deaths, gasping at the surface, finrot, ich, fungus...Until then it will all look ok - but it really isn't..
The only way to cope with the cycle when you have fish , and can't move them elsewhere is either
a ) resign yourself to the fact they are going to die and just keep fishing them out (generally not the favourite choice on here ;-)
b ) water changes - lots of them. Test your tank morning and evening for ammonia. Everytime it is above 1.0ppm do a 20% water change (dechlorinate in the jug by the way). If its above 2ppm do a 40% water change.
Hope that helps - you've got some lovely fish in there!
aj xx