I have 3 pairs (darwin ocellaris/pink skunks/regular ocellaris) in a 300gallon. It's no walk in the park and took a few tries to get to 'stability'. When people say it's not recommended, they're right. If not properly planned and observed carefully, it can end up in disaster. I have regular squabbles that are very similar to tangs fighting -- things are fine most of the day with regular posturing, vocal chatter, fake attacks and the rare actual attack. A few things that are definite trouble.
- Aggressive species like Maroons, Tomatos, etc.
- Different sized pairs. Each needs to be able to defend it's anemone.
- Attempting to move one pair to another anemone.
- Proximity to each other.
Possible - Yes. Recommended - No.