How do you know your tank is cycled?
A cycled filter will convert added 4 ppm (or thereabouts) ammonia to nitrite and hence to nitrate all within 12 hours, have you checked this? If it does not, it is not cycled.
'Instant' cycling compounds aid cycling at best and at worst, they do nothing. A fishless cycle is done by adding ammonia in precise doses and checking water parameters every day, more often towards the end of the cycling.
I may be wrong but I suspect adding fifteen cichlids to your tank based on Nutrifin Cycle addition alone will result in fifteen deaths.
Read the cycling threads on this forum for accurate information on preparing a filter for fish.