Thanks guys. I think what I've come away with from this is that the aggressive clown species should be shown great caution with inverts, not just other fish.
In 55gal and 20gal land, I have also decided to move one of the damsels back to the 20gal and keep one in the 55gal. The reasons are not what you'd think though. The slightly larger damsel adjusted to the new tank immediately and loves it, so that's the one that's staying. Perhaps I just didn't wait long enough for the smaller one to get his confidence back after being in a new tank, but he's had a few spectacular, water-splashing freak-outs when I've walked into the room too fast or picked up a shiny object too quickly, and he was never that much of a live wire in the 20gal. Since these two damsels never showed the same degree of pairing behavior as with a previous combination I had (one of the original pair died in the great sea hare nuking, so the nervous little dude was a buddy replacement), I decided to move the nervy damsel back to his old home since it was vacant again. I'm not dead set on maintaining another aggressive fish pair and would rather see both thrive equally. It's amazing how different the personalities are sometimes within a species. The nervy one is also very friendly to the point of being poke-able at times while the other one is pretty indifferent to me.
In 55gal and 20gal land, I have also decided to move one of the damsels back to the 20gal and keep one in the 55gal. The reasons are not what you'd think though. The slightly larger damsel adjusted to the new tank immediately and loves it, so that's the one that's staying. Perhaps I just didn't wait long enough for the smaller one to get his confidence back after being in a new tank, but he's had a few spectacular, water-splashing freak-outs when I've walked into the room too fast or picked up a shiny object too quickly, and he was never that much of a live wire in the 20gal. Since these two damsels never showed the same degree of pairing behavior as with a previous combination I had (one of the original pair died in the great sea hare nuking, so the nervous little dude was a buddy replacement), I decided to move the nervy damsel back to his old home since it was vacant again. I'm not dead set on maintaining another aggressive fish pair and would rather see both thrive equally. It's amazing how different the personalities are sometimes within a species. The nervy one is also very friendly to the point of being poke-able at times while the other one is pretty indifferent to me.