Interesting! I’ve wondered this for a while, not just with zoas but other things too like hammer, Duncan, etc. It would seem that they’re on their own since sometimes there are just a few polyps not doing well, but that doesn’t really make a lot of sense since the zoas in the middle of the colony will no longer produce babies so whatre they doing with all the extra energy that used to go towards babies? I think zoas do share energy because it doesn’t really make sense for them not to. Why would 1p frags have a higher chance of melting than multi polyp frags if it was every zoa for themself? I’m pretty sure the whole theory behind 2+ polyp frags having a higher survival rate is because the zoas share energy :). Also, larger colonies grow faster which would make sense of zoas shared energy. All speculation, but I think it makes sense!