It shouldn't be necessary. But if you're adding an extra drive, cooling should be looked at. Your case has a fresh air intake in the front at the bottom. Air should directed from there over the hard drive cage. Exhaust is via the fan in the rear, and via the power supply. If the case has a mount for a fan in the front intake, and no fan is present then you can add one there as long as you replace the rear fan with an appropriately higher-CFM fan. Air flow through a case is not as straightforward as it seems, and as often as not, fiddling with fans can worsen heat problems as easily as fixing them.
A lot depends on what cooling is present, and whether the air flow is being directed across the hard drives correctly.