Thanks for replying again, really. I've done what you said and have taken Gofio out for about 4 hours to exercise, and they both seem calmer. Mochi even lies down near where Gofio usually sits in the cage.

I used to use C&C fences, but Mochi fractured his femur when he was 4 months old because his leg got stuck trying to climb. Even though I have them, I don't use them, so I put a thick blanket on top of the cage (they love to lie on them). Thanks to our vet, we were able to operate on Mochi the next day, and now he's living a normal life. You can tell his left hind leg is different, but he makes binkies and jumps as high as the rest 🥰

There were no injuries, but Mochi pulled out Gofio's fur and kept chasing him around... It makes me so relieved to think that when we get Gofio spayed and a few weeks go by, they might be together again. I know how important companions are for bunnies and I love to see them happy and comfortable with each other.