Typically, different morphs/species of frogspawns will co-exist without stinging each other. Even hammers and frogspawns will co-exist. But, for every 100 happy combinations, there will be a few instances where stinging sweepers are grown and used to attack another frogspawn/hammer. :irked: Another coral frequently mentioned as co-existing with frogspawns and hammers, is the torch coral. In my experience, torches are most likely to sting another Euphyllia sp. coral, but again, I've had torches that played nice.