Help! I killed them all!

[puck]

Started a new 60 gal. saltwater tank. Added mature salt water from dealer, 20 lbs live sand, 20lbs live rock, 3 damsels and 2 tomato clown fish. a couple days later the clownfish turned slimy/white then died. A week later the Damsels died 1 each day for 3 days.

The water tested fine throughout. (all parameters; pH, salinity, amonia, nitrites, nitrates)
I did have a couple temperature fluctuations of 2 degrees or so.

I think I made some mistakes though.

1 The salinity was a little higher than wat the dealer wanted ( but still in range) so I added 2.5 gallons of room temp distilled H2O.

2 when I bought the tank and filter it was a used setup for freshwater, so I washed the tank, filter and ceramic filter media with dish soap. I rinsed it very well.

3 My brother gave me some old coral from his reef tank that cracked about 4 years ago. It had been stored in a moist ice chest.

Do you think any these mistakes were enough to kill off everything?

What should I do now?
complete water change? even though I have the tank cycled already.

My current setup;

60 gal acrylic tank
Fluval 404 (I just ordered a wet/dryfilter)
300 watt heater
Red sea Prizem protien skimmer
36" florescent light/hood.
power head in tank for circulation
1 air stone in tank
20lbs live sand
20lbs live rock
20lbs old coral from reef tank that died 4 years agao

[twflys]

i'm a newbie........ so, don't trust me on this but, maybe a copper problem. Since the tank setup came from a freshwater it might of had some traces of copper, usually from medicines or additives or perhaps one of the fish was carrying a disease that spread.

May the fish gods be on your side!
twflys

[OrionGirl]

I never use dish soap on anything for my fish tanks. I can never be sure I completely rinse the soap off, and the residue could be damaging.

Adding that many members of the damsel family is asking for problems. Damsels are highly territorial, and will beat each other up. Clowns are damsels, by the way, same family.

Unlikely that ammonia didn't play some role in the deaths.

What I would do is to buy a couple cocktail shrimp and toss them in. Let them rot and then monitor the ammonia/nitrites. Cycle the tank completely before adding more fish.