scolymia, trachyphyllia and Acans atacking eachother

[dcom]

Hi,
I've seen videos were lobos and scolys lye next to each other and I really like the color contrast but in my experience, whenever closer, these corals attack each other.
In two ocasions my snails or fish had pushed an acan and a trachy next to a lobo and the lobo has digested part of those corals tissues. I've lost a piece of the acan and a big chunk of the trachy's head.
For now, I've placed epoxy rings to prevent them for touching each other.

Is it just this single lobo that is so aggresive? or should I definitively maintain a good distance beetween all of these corals?

PD: in the pictures, the circular purple/green piece is the killer. The other two are its victims
Thanks

 

[sdbc]

All corals will potentially attack neighbors of different species. Last month I had to move a tiny Favites frag that was 2 inches from a 12" wide Sarcophyton because the Favites was attacking it. You definitely need to keep space, but how much depends on the species, so do your research.