Yes chloramines are chlorine and ammonia. When you dechlorinate the water it leaves ammonia behind. Not much though. The API test kit measures total ammonia (TAN) this is a mixture of ammonia and ammonium. Free ammonia is the toxic part of TAN and the API tester does not distinguish.
The percentage of free ammonia in your aquarium rises with temp and ph.
Have a look at the link.
http://www.aquariumadvice.com/forums/f12/your-guide-to-ammonia-toxicity-159994.html
You will probably find you are in the green without using prime. But the problem is nitrites. The more TAN the more nitrites. Nitrites affect fish depending on size and species. Just watch for both rising.
