What is this?

[Marsh980]

So an interesting mix of things hiding inside a crease of my trachy.

There is definitely GSP and one Aiptasia but what is the thing with the shell? Looks like a mollusc.

There’s also a little bubble algae grown on it too. Is it time to take out the tank and give it some TLC and sort out the hitchhikers. I don’t really want the GSP on their either

Any help would be amazing

 

[dwest]

Agree. Looks like a small clam shell to me.