I don't get it... Please help to explain...

[rakabos]

One thing i can tell you is that if something is wrong with the water the first thing to die is usually the inverts which make up a cleaning crew, shrimps, snails etc. So the fact they are fine along with the corals means that the clown was probably sick when it entered your tank and you could not have forseen it would die. Don't stress over it too much, deaths in the tank is unfortunately part and parcel with this hobby.

It could have been from cyanide poisoning also, this is how many of the less scrupulous collectors catch the fish, and the resultant internal damage only kills the fish a few weeks later. Chin up and go get a new one!

 

[rakabos]

Oh and if u can, try and get tank bred clowns, they are good to go when u buy them

 

[Sammy]

Dude, I know how you feel, try loosing a yellow tang, regal tang and a sailfin all within a month after they bought, all corals and other fish doing excellent and water params 100's.... that's a big for me ???

 

[rakabos]

For me the REALLY depressing part is knowing these fish were just fine in the ocean until we took them out

 

[Mauritius-aquarist]

It could have been from cyanide poisoning also, this is how many of the less scrupulous collectors catch the fish, and the resultant internal damage only kills the fish a few weeks later.

That could be a possible reason.
If I was you, I would inquire at the LFS, on the origin of the clownfish.
Another thing could be the clownfish disease, which gives very little time for you to identify. It have happened to me, I caught some clowns and kept them in good water without myself knowing that the fish had the disease. Things went so rapidly and you find them dead without initially knowing the cause.

Don't lose hope bro, clownfish are supposed to be a beginner and easy fish. Just, ensure yourself next when you're buying one that it's completely acclimatised and eating happily.
Cheers bra