I thought they were flatworms but now I don't think so

[seabass]

Hundreds of these showed up on my sand bed. They seemed to pop up very suddenly. They are capable of changing shape, but don't seem to crawl around like a worm.

 

At first I thought they were flatworms, so I removed as many as I could and treated with Levamisole. To my surprise, they continued to reproduce in my tank. I removed a few new specimens and treated a cup of tank water with two drops (which would treat more than 2 gallons) of Flatworm eXit. They didn't respond as flatworms would; however, they did retract into a ball.

 

Best photo I have at the moment:

One is attached and contracted, while the other is not.

 

Changing shape slightly:

 

They contract when removed from the water:

Shown on a paper towel.

 

Any thoughts as to what they are?

[Sticky Reefer]

Flat worms come in all shapes and sizes...this is a commen flat worm..the yellow damsels do a good his of controlling them as well as small wrasse six line,corris exc. Other wise you can go with chems but is that's scary lol....

[seabass]

Looking more like baby Rock Flower Anemones now.

[sanchez]

that's really cool if you had a successful spawn. How many adults do you have?

[seabass]

How many adults do you have?

I have five in that tank. I've never had one split. I'm wondering if, in nature, they only reproduce sexually.

[cheryl jordan]

This is cool.

[Builder Anthony]

man.....if so you hit the jackpot.im not suprised your tank is unique.i forget if your coldwater or not though.if warm id like to get 3 or 4.i would look for bubbles in the parents teneacles.i think i observed aptasia reproduce like that.

[seabass]

Thanks everyone!

 

i forget if your coldwater or not

The tank is definitely tropical. I assume that the 'bubbles' you speak of are buds/babbies which are still attached to the adult. While I haven't observed this, it might have been what happened.

[seabass]

Today:

[iball1804]

Wow! Pretty! I've got two. They're gorgeous