I'm playing the first area with fishermen and I've been piling them up in granaries for when Pharaoh asks for them. Now I finally need to send them, but it says I have 0 fish in the commerce screen. I look at my granaries, and I have 2600 fish stored. What's going on?

when the resource manager looks at your stock it doesn't look at your granaries , it looks at your storage yards, right click on one and set it to only get fish and you will be good to go, as they will fill storage yards before granaries

Thanks, that did it.