[SleepyPirate]

I bought Two little fishies Marine snow today along with some Marineland Premium activated carbonfrom Big Als and added both to tank today. The marine snow stinks of rotten eggs not sure if thats normal. I came only 2-3 hrs later and found my Yellow tang lieing on the sand bed and rocks. I tryed to move him and he he did move but only to land himself sideways in the sand again, he adjusted back to the spot he was previously in. I did an anomina check its its at .25ppm so I changed 5 gallons out of my 50 gallon tank. Could the the carbon or marine snow that smells horrible be to blame for this?? Iv had tang for over a year and it just today started to act werid. below is a pic of him now. Any ideas whats going on?? all other fish are acting normal.