My clown just had this
My clown just had this
My clown just had this exact same thing last week. I posted it on here, with pics, and nobody could tell me what it was.
Mine had only been in my tank for a week when it developed a white "bubble" directly in the middle of his forehead, a little lower than the one yours has. After about 3 days, the bubble "popped" and went away. His color remained good, and he ate aggressively throughout.
That was about a week ago, and he is still doing great. The spot is completely gone, and he is acting normal. I switched to flakes with garlic, which my LFS advised me to do.
Good luck! Let me know how he does.