Is this coral behavior normal?

[rividewave]

I've had this coral since it was tiny, just one head, and it's been thriving. My other corals are all doing fantastic, looking healthy and vibrant. I first noticed this issue with it last night, and this morning it still looks the same - is that normal?

[Mango]

Looks like something's stressed that one head out and it's receded. It's probably just temporary, should come back on its own.

[ravenoak]

I let it be for a day or two to see if it recovers, if not, I check my water parameters, specifically Mg, Ca, and Alk, to rule out any issues there.

[zenix4]

Your hammer coral's doing alright, just give it time to mature like mine has, it'll be fine.

[vyno9]

I'm not sure what you're looking at, but I'm a bit concerned about my coral.

[rusticore]

Hey Paul, I've got to say, I think that hammer coral might be a bit too close for comfort to the coral on the right - is that a hairy mushroom or a leather? You've got a lot of experience, but hammers can still cause some damage if you're not careful.

Foundnemo11, I'm with you, that doesn't look right. Take a closer look at the second picture, the head above the deflated one - there's a small part of it that's not looking great, the part closest to the deflated head. Just thinking out loud here, but could something have fallen on it? Maybe some salt crust from the tank lid or a stray snail? Or perhaps a piece of that birdsnest above it broke off and landed on it?

[felinxo]

If it gets too close, the hammers can also start sweeping and break those gflintix9s, just something to keep an eye on.

[zenix4]

My hammer's a beast, been growing for ages, got a few heads on it now, it's a real showstopper.

[Spark]

My hammer corals took a while to mature too, but they're awesome now.

[rividewave]

Still looking the same, any ideas? It's been fine for years and all other corals are doing great.