Gus and Puddles got along before this just fine?
What’s going on is that it’s breeding season, generally around winter and through spring geese get very hormonal, ganders can get very territorial and possessive, and depending on what dynamics are at play you can expect aggression directed at others or at each other to varying degrees.
It could be misdirected mating behavior like
@sourland sugested, males will mount males and females will mount females when the mood takes them, sometimes this isn’t an issue, sometimes it can start fights.
It could be battles for dominance, territory, and partners too, “breeding season horomones,” they may sort it out for a few days, and then be back fighting each other for the rest of the season until their horomones settle in mid spring.
A lot of it depends on their personalities, things can change with geese over time too.
For example I had two gander brothers who never fought, they had perfect harmony, one sadly past away and the other ended up bonding with their dad, which was surprising because they had been mortal enemies before, now father and son are perfectlily happy and they never fight with each other.
I have two other ganders who are bonded with each other, in breeding season they squabble, but work it out, the rest of the year they don’t have issues.
These two groups on the other hand can never be in the same area together or there will be bloodshed, at one time they got along okay, but not anymore.
So for your situation all I can say is things could sort itself out in a few months, it might be permanently resolved or it might be a seasonal issue that resurfaces every year. The 7 month old is still learning his place in the group, it might make him more aggressive and he might be more tame by the time he’s 2, or he could just get worse.
You might have to try different set ups, seperating him switching who he’s paired with, maybe pairing Gus and Puddles together once breeding season is over to make them learn to get along.
It may be an ongoing project.
