hello all im new to this hobby and am having my share of dificulties. started tank with fish about 7 or 8 weeks ago using a fluval 304 not knowing anything about cycling at that point i stocked the tank with a couple of red belly pacu's and some small tri colored sharks and some platy's . which all became a buffet for the pacu's not knowing about fish compatibility either unfortunately my lfs wasnt very helpfull. .at first the pacu's werent bothering the other fish then bammm i guess they got big enough to start eating other fish? it took about 3-4 weeks before the pacus started eating all the other fish, ok back to my problem, in about the 3rd or 4th week the water got really cloudy and i figured filter needed to be cleaned (again not knowing about the cycle thing) so i cleaned it all of it even the media i should of left alone, water still cloudy so i asked the lfs and now the tried to explain the cycle thing and told me to do a water change. cleaned the gravel and replaced about 1/3 the water was better but still not crysal clear so i then tried "crystal clear that did it but only lasted a week. then i descided to find a new home for my pacu's. now its been about 6 or 7 weeks and figured cycle is over ( I was told takes about 50 days ) i went to my lfs and purchased 6 small tiger barbs and 4 redfin tinfoil barbs . the next day the tinfoil barbs were swimming upside down and died a few hours later, swim bladder prob? and i lost 2 or my small tiger barbs and the rest dont look too good, took a ammonia test at that time and found to be .5 so now to my question is the ammonia high due to the cycle being slowwed down due to my cleaning the filter and water change too soon or something else? what can i do to save my remaining fish? should i just keep my fingers crossed and hope the remaining fish make it through the remainder of cycle?