LPS gurus... can these touch at all?

[Myka]

Those are definitely all Favia sp. Ime, some Favia can touch eachother, and some can't. The ones that can't will create a very large patch of dead tissue because Favia can produce very long sweepers. I've seen sweepers about 8" long. Those pieces are small enough that if any of those got mad it could kill the whole frag.

With LPS, you have to experiment. It really varies, and you can't just go by genus or species even. Place them close enough that the flesh is actually touching. Watch them very closely for the next hour. Ime, they will usually start trying to kill eachother within 5 or 10 minutes if they are touching.