Guys is my hammer ok? you can see some of the tentacles are retracted near some of the sides and centre, second picture is when it looked great. My other hammer is doing really good tho.
It can be many factors affecting them, too much flow, too much light, alk swing, too much nitrates, too low nitrates, calcium level, magnesium level.
whats your parameters?
what kind of light you have?
they could be just acclimatising to new system.