Hasi said:Adding all the fish at once can be too much bioload for your good bacteria to handle, that is why they say to only add a few fish (3 - 4) a week. Considering your fish a quite big you could of disturbed the balance.
I would suggest often water changes until you can do a test of your water. Do a water change of 20% a day or every second day. If possible take a sample of your water to your LFS to get a test done on your parameters.
Goodluck and sorry bout your loss
Trust me i didnt wana throw them all in the tank at once. I was only gonna be useing it for my smaller fish thats the reason it got set up. Now i got everything in it. And altho they been moved twice in aweek. They eating. Ima just keep doing small watter changes on it for about a month screw it