IMO and fish that size it's hard to kill them with a little ammonia if there isn't something else wrong with them. I lost an azul and an orino moving from my 180 to 450g. I'm not 100% sure, but I believe that the bucket I used to acclimate wasn't rinsed enough from me pouring out water test chemicals. I did cycle my big tank for a month with comets and my tsn. Then I put the pbass and other fish in fairly slowly. I went from 0/0/5ppm nitrate to like 10/0/5. It stayed like that for a while and none of the fish that were in there seemed affected by it at all. I know it wasn't the best situation to have them in, but since they were healthly to begin with, it didn't phase them. Even if your tank wasn't done cycling, I doubt that's what killed them.