Anyone who travels should carry a copy of the regulations or have it pulled up on their phone it’s not a problem in Orlando where I am since it’s a big hub for coral lol but some places less soI'd be interested on the success rate of getting corals in water through TSA security. Maybe if you keep them within the 3.5oz/1qt sized bag you might be ok but you won't be able to fit many in a 1qt bag.
Even if the regulation posted above allows corals then there's no guarantee that TSA will let them through. I have had scissors confiscated in the past that should have been allowed through (they were short enough to be legal for carry on) but there was no arguing; they weren't interested/didn't have time to check the regulations so I had to throw them away.
What would you do if you get to security and they say no? Is it worth the risk?