Well, they’re not quite the Jules Verne size that will eat you. But they are more than two hands wide. I’m used to opening the shell completely but that’s not the case. They open this wide and have a mouth to feed. What’s interesting is that they come in so many colors.
You usually don’t see two together. I’m partial to the blue ones.
Depending on the age, some look worse for wear.
And they get embedded/surrounded by coral so it’s hard to see how there’s room to move.