Thanks, now it's working!!!
I tried to make the bucket, as the guide said and it's not working. Instead of getting a bucket filled of my fluid, I get the one filled with the material of that fluid block (e.g. Block basicFluidBlock = new BasicFluidBlock(basicFluid, Material.water) when I pick it up with the bucket I get a water bucket)
Here's the Main Class
Here's the BucketHandler Class
I had to comment @ForgeSubscribe in the BucketHandler class because I got this error ("ForgeSubscribe cannot be resolved to a
type")