Hydrogen peroxide can help you clean a guinea pig abscess, or a horse abscess. First though, the abscess has to be open. Here are 2 pages I wrote about cat abscesses, and treating cat abscesses with hydrogen peroxide. [page 1] and [page 2]
I wrote about cat abscess home treatment first because it’s what I have experience with. However, the information about cat abscesses also applies to a rabbit with an abscess, a guinea pig abscess, a horse abscess, or a goat abscess. I would think it would apply well to all or most mammals.
The information on my page about finger infections and skin infections (in humans) would also apply well to skin infections on horses, camels, pigs, sheep, rabbits, and guinea pigs.
As I said regarding cats, how well the peroxide works will depend on how bad the infection is, and how long you keep the peroxide on the infected area.
As with all things, go gently with your animal friends.
I don’t know how peroxide would affect feather or scales so I would hesitate about using hydrogen peroxide on a bird or a lizard with a skin infection. Hydrogen peroxide will certainly kill bacteria, but I don’t know about using it with birds and reptiles…. I’ve only personally used it with humans and cats.
Do not try hydrogen peroxide directly on fish – different fish species are more or less sensitive to hydrogen peroxide, and you could easily kill fish by putting too much hydrogen peroxide in their water.