Dead fish...any ideas?

Ok yes i am new to SW tanks but im not a complete idiot. I just got my firefish yesterday and he was fine. I came home today he seemed fine swimming around normally i fed my tank and he ate a bit and kept swimming. Well an hr gores by out of the corner of my eye i see him swimming very eratically. Bouncing around, looking like he was having trouble staying upright.Eventually he just stopped and floated motionless and got pulled to my filter intake. He died . I checked all my water parems Ammonia-0, PH-8.2, nitrite-0, and nitrate around 30 id say. A little high i know could this be the cause? Salinity was fine 1.022. That at the moment is all i have tests for. I have a clown and goby and other inverts living in there happily so i figured if something killed him it would effect the others as well. My acclimation process is as follows i submerge the bag still sealed into my aquarium for around 20 mins for temp to adjust. I then pour the bag water and fish into a large jug. I then drip acclimate for around 45 mins to an hr with around 2-4 drops per second. After that i gently place him into the tank making sure not to add water from pet store to my tank then top my tank off with salt water i premixed with same PH and temp. Then i turn light off for around an hr or so for him to calm down and adjust. Am i doing something wrong here?

Sometimes fish just die, your levels from what I can tell arent really off and if nothing else seems affected then I would guess it was something with the fish. I like to keep my salinity a bit higher then that but it seems you were pretty careful...other more experienced people will chime in though

+1 MW -- it happens, and sometimes you never know why. Maybe your LFS had just received him, and didn't give him time to relax before the next move to your tank. Sometimes you never know why. Sorry to hear.

+1 Everyone

Sorry about your fishie

Thanks all i took his body back to the fish store where he looked at him. Apparently his gills were covered in a thick mucus. Not a good sign. He blamed it on previous care and not mine since i only had him for a day. Really sucks was a great looking fish. Gonna miss him. Ive had some bad luck already, dead clown (due to my devil emerald crab) and now this. ugh.

Sorry to hear that about your fish...but don't blame yourself, you've done everything right. So +1 everyone.

It happens got a flame angel he died with in 24 hours. I was verry sad that is one of the main fishes I wanted. hang in their.

Sorry to hear about your loss! I would raise your salinity a lil bit to maybe 1.024 to 1.025. Just my opionion

Thanks, i think i will. Actually i had my friend check the accurcy of my hydrometer with his refractrometer and it was out by .0015 so i guess it is more around 1.023. I will gradually raise it up with some water changes.

you can just top off with saltwater to raise your salinity. Also you can get a good refractometer on ebay for around $20, which will pay for itself in a year because you need to replace hydrometers every 6 months or so.