Frogspawns as well as all other Euphyllia's are aggressive corals. DO NOT place them near anything else unless it is other euphyllia's and even that can be a problem (Torches are known to fight with other torches and the like). As a rule of thumb, give them AT LEAST twice their size/reach for space because they send out feeler tentacles that extend VERY LONG! As an example, I have a nano with my frogspawn and got it when it was 1" and 1 head big. Six months later, it is now 4" and 9 heads total but is still 8" away from it's nearest neighbor (a 4" Crocea that I can move if needed). It is also good if you can place it in a known current. Meaning, a torch's tentacles will follow the flow so if the flow goes front to back, the tentacles will too! Keep that area clear for growth.
Good Luck!