should try to move the shrimp and clown temporary out from your tank. I have smiliar encounter which my maroon clown trying to house on my hammer. Once i have removed and sold my maroon away. Hammer opening big as usual. From my personel experience, i found that clown like to host themselves to hammer, elegance, and bubble, unless you have a ammone.. but thats doesn't guaranteer too. Luckily, i have only 1 false clown now.. and every night, it rest on my brain. Since my brain still shows sign of fresh and healthyness, i just leave the clown inside my tank.