Gosh what a conundrum. It's hard when a child does not like water.
For me, I don't like juices given at this age.. .my kids were not given juice until after 2 years old, and then only diluted 50-50 or more. And still now.
You can try VERY diluted juice. See if your baby will take that. Or, for my son, he only likes water if there is ice in it. So try that too. Sometimes it's just the temperature. My son likes cold things. My daughter will drink anything. And my daughter also went through a 'stage' where she liked 'carbonated' water (like her Dad). So that is an option too.
Oh, or try making ice-cubes using juice... then add that to the water for your baby. That way, less sugar and give it a little taste.
Also, it's the way you serve it. Try it in a sippy cup. Or straw cup. Or maybe squeeze a little orange juice in it directly.
Is your baby drinking other things? whole milk? Formula? if so he is still getting hydrated enough.
Or like Riley said, make your own! That is the best and easy.
And yes, they need the milk fats....its an essential 'nutrient' needed for brain growth and development etc.
But going back to 'juice'... well, maybe ask your Pediatrician? Some people also like the V-8 "Splash" drinks as well.
Good luck, I know we Moms have to try so many things sometimes! LOL
All the best,