Tanks show current values: code, name, type and status — carried by the same names your screens show, not codes you would have to look up — plus the branch the tank sits on and its maximum capacity.
Batches are where the farm's life actually happens, and the aquaculture numbers attach to them: feedings are recorded against the tank a batch occupies, mortalities against the batch that lost the fish, and a harvest is the batch's own closing event — the harvested quantity is the batch's live count at harvest, and its cost is everything the batch accumulated, stocking plus feed. There is deliberately no "harvest product": a batch grows a breed, and breeds are not catalogue products, so harvest figures are read by tank, batch and breed rather than by product.