In my experience issues can aries with any of them. some torches don't like to be placed by other torches, some frogspawn and hammers don't get along, and others comingle without issues. I've found the best bet is to place them near eachother so when their fully open the tentacles will just touch and watch for one to pull back from the contact. I've also seen better results to coral just brushing another and then slowly growing closer than starting almost on top of eachother.
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