Corals to avoid?

[Mono]

Are there any corals to avoid at all costs because they poison other corals in the confined space of an aquarium? I don't mean corals with nasty stinger tentacles like a tooth/galaxy coral. I mean one which poisons the water killing off other corals regardless of where you place it.

 

[ZoWhat]

Galaxy corals have 12in sweeper tentacles that sweep the water in the middle of the night stinging other corals like crazy

Heres a video of daytime sweepers; at night they can go 8-12in in reach

 

[Mono]

Oh I have seen those. But I'm talking about guys that nuke the whole neighborhood.