Most our dogs love water until something happens to them in the water that they get scared. I have a couple of dogs that have almost drowned and are hesitant to get in the water but over time get over it and cross or they find somewhere else they feel comfortable to cross. The most recent incident with one of my dogs was our dog Cody got pushed in freezing cold water by a hog, it was a part of the creek where it was two walls on both sides so no way of getting out of there, he was in there for quite a while, by the time I saw him he was tired and almost about to drown. We got him out but for he rest of the weekend he would not touch water!!! They either cross or get left behind in our group! Like I said most of the time they cross but there are some dogs that just dont want to have anything to do with water.
I would leave him behind if your comfortable doing so. Give him time he will figure out that he will have to get in the water or get left behind.
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X3 We just leave em behind and then they figure out a way to get to us.