Oh well I guess it's more common than you think. Thanks everyone.

Now here's a question, going shopping tomorrow for replacement. Would you buy one more or three more for better odds ?

Definitely only keep 2 total in the tank. Anymore than that will eventually lead to clownfish being killed by the dominant pair.

I had the same thing happen in a 30g nano! taht was infested with Bristol worms! they ate my clowns! I had some as thick as my thumb! there was over 500+ of them! I they were spawning ever 3rd night! so they just ate my fish lol!

The question is will it compatible???

Was it the female(large) clownfish that disappeared or the small(male) clownfish that disappeared?

Large female gone. Male hung upside down by my mag cleaner for two days but is venturing around the tank again now. I do have a lot harmless orange worms that come out at feeding time. Never seen one aggresive in any way. The clowns were in the upper half of the tank waiting for feeding time.

Since your female has passed away, you could look for a larger clownfish than your current one, or a smaller one. I would try to avoid getting one of the same size to avoid them doing a lot of fighting to determine who will become the dominant clownfish.

What kind of clownfish do you have?

Thanks ponokareefer. That's what I will do. Ocellaris.

My new purchases
 

http://www.canreef.com/vbulletin/album.php?albumid=635


Bought a new clown and pj cardinal. The clowns are already happy and even hosting playing in my green hammer. Yes I see the algae. Currently started bio pellets with phos down to .11. A work in progress. I seldom ever clean my back glass. Growth there stays out of the display. I attack my aptasia regularly. My gramma and my cleaner are one year old now as is the tank.

Update. Everyone is doing really well together now. My new clown, slightly smaller than the other, has already assumed the female role. They play together rolling around in my green hammer. They are a joy to watch, so I hope they stick around. My gramma doesn't even chase them away anymore. I think they wore him down.