That's a good pic. And I see the swelling it could be from jumping down from the pool or he got his foot caught in something either way its an injury. Be careful soaking him in Epsom salt water if he is drinking it he can get dehydrated. If I have to soak I use a bucket and put both legs in it makes it easier then just hold the duck while soaking. I use a cup of Epsom salt to a half gallon of warm water you'd def not want him drinking that. Bottom of his foot is clear of swelling redness etc? No scabs like bumble?
How does that toe look where he lost the nail?
How does that toe look where he lost the nail?