Need help bad dead fish after 3 days

[b wells]

Ok i just switched over my up and running 75 gallon Tank for many years to a 120 gallon tank. I used all the old sand with 3 new bags, used the old water and added 60 gallons new and all old rock. I had a few clowns an eel and Anemones come over in the new tank with no problems. The water test perfect with Salt at .025. Its been cycle for 3 weeks and added smart start, the issues is i have added 3 yellow tangs and 1 ray. The ray has been doing well but the 3 tangs all died with in 3-4 days. I retested and week and half later added 3 more yellow tangs and same thing, 3 days later all died. ray and rest of the tanks is great just do not seem to understand why new fish are dying. I have feed both shrimps, flake (sm amount) and even added garlic to the food. The tangs where eating on day 2 but seem to get ick on day 3 .

Looking for any ideas?

[Sk8r]

PRobably ammonia poisoning---time of death possible with kidney damage on entry. I trust you mean 1.025. Stop adding fish. Tangs are fairly delicate. 1 tang in a 120 is pushing it. Ich is probably opportunistic, taking hold as the fish declines in health, but possibly also your source is contaminated, because ich breaking out several days on is not an uncommon situation---fatality that fast indicates a double problem. Mini-cycle on the tank move. What is your alkalinity? Garlic won't help except as an appetite stimulant. Your sand-dwelling fish and clowns may be fending off the infestation of the sand via particularly thick slime coats, but you need to remove EVERYBODY of fish in tank to quarantine and treatment, and keep that tank fishless for 72 days to let the ich that has now nested in the sand from finding a host and reproducing again. It's a complex problem ---a) probably poisoning, now cycled through and b) ich from your fish source adding to your problems. THat's the one that requires the 72 day standdown. I hate to welcome you to RC with such news, but the cure is going to be that fishless fallow period, plus observation of your other guys. TTM, outlined in the sticky posts, is the fastest way to deal with possible ich in a set of fish. You can use a barrel for your second tank if necessary.

[GimpyFin]

Ammonia is a possibility as sk8r suggested. If you examine the fish did you see any red marks/blotches on the skin or near the gills? That would be a good indication of ammonia poisoning too. Have you ran a test?

[ericarenee]

i agree with above

test ammonia and nitrite

[b wells]

Ammonia and nitrate both test 0 and no red marks or blotches. first day active second day active with min eating and 3 day active with signs of ich one more then the other then 3 night 2 dead and one swimming side ways