so few months back i wanted a school of red tail payaras. couldnt find them and havent heard back . so i called a local place and told them im coming by today to pick up the remaining ATF's he had in stock. litterally as i arrive my buddy calls and says the tats have arrived . all 6 so ended up picking up 6 x 3.5" tats. been a few months now i had them all housed in a 7ft 210 gal tank. atf"s were barely 4" aswell. so 2 weeks ago i noticed my tank had a small leak. bc i didnt have a similar size tank i was worried about making too many moves into new environments. so the first week i couldnt find a tank. second week comes along i decided i need to fix it now bc it just got worse. i put the rtp in a 75 gal. and my atf in a 4ft 150 with the 6 silver dollars and catfishes. i took all the media except for the k1 that was in a 100 gal sump under the 210. this tanks been up for over a yr est with no issues ever. so i split the media in half. the atf tank has a ac100. and i jus dropped the media in the middle of the tank in mesh bags. the 75 gal is acrylic and ac110 couldnt fit on it. so from the sump i take out the 3 established sponge filters i keep for emergencies and put it in the 75 aswell as bags of media in the middle of tank. next day i picked up my TEMP tank until my 210 is sealed and done. give or take 2 weeks. temp tank had a leak in overflow box so i figured id seal it now while its empty. 24 hrs later i set up the other tank and go and fish out the payaras. i noticed 2 of them had ammonia burns on there side. so in a panic i figured the other tank is up and i have it filtered thru my old sump. withing the first 2 hrs. 2 died and yesterday morning another 2 and this morning another 1. tested water no ammonia and im also doing 30-40 percent wc daily. just incase. now my atfs are feeling crammed in the 4 ft tank but im worried to put them in this one and have em die off.