if I read this article correctly http://forum.simplydiscus.com//index...;threadid=1218
Prime will not get rid of chloramine as there will still be an element of ammonia in the water and this was removed by placing a cycled filter in the residual water ....
Im no expert but it sounds like your fish are suffering from some kind of acidic water damage or burning of the internal organs caused by ammonia perhaps ammonia test kits when dealing with Chloramine give false readings so it is hard to establish exactly how much if any free form ammonia is present ....
Perhaps other members more qualified could answer your post I too have been advised that Chloramines are in My tap water something I need to investigate further myself ..