Help Needed

[RocknBeatles84]

I have have had a stable tank for over a month so I bought 2 clown fish and an Orchid dottyback. They have lived together for 2 weeks.

All were doing great untill I bought a diamondback goby from Petco recently. The goby lived for a few days then I observed him acting strange and swimming erratically. He then looked as though he lost his breath and had a heart attack. He died and was eaten partially by my Halloween crab and some others.

They day after his death, the dottyback and one of my clown died as well. Then the day after that my last clown died. I had my water tested by 2 fish shops and they confirmed all was good.

After the deaths of my fish I have completed a full filter cleaning and replaced 5 gallons of tank water with good tested RO water.

My current water parameters are as follows:
Alk-10
Ca-460
PH-7.4
Mag-1120
Sal.1.026
Am-0
Nitrates-0
Pos-.25
Temp-78 degrees

Not sure as to why all my fish died and all inverts are fine

[Dayson]

DO you QT your fish? If not, im guessing the goby brought in some kind of parasite that wiped everyone out. Petco isn't exactly known to have the most healthy living conditions.

[jml1149]

The fish at the Petco by me are always covered in ich and crap. QT is an absolute necessity.

[jml1149]

Wait is your pH really 7.4 and your Alk 10.0? That can't be correct, how are you testing your pH? If it's really 7.4 that's way too low and would have killed everything.

[gone fishin]

your time line suggest something along the line of brook or velvet. the link has a diagnosis section see if anything fits.

http://www.reefcentral.com/forums/showthread.php?t=2389659