If you are going to actually put fish in that fish box it is essential that you make sure the drain to the back bilge area is clear of all debris. Dead fish parts and blood has a very aromatic smell after just a few hours in the sun, and even more so days later. Even more important than that though is the fact that the underside of your deck and the stringers are wood, and wood NEEDS to be kept as dry as possible to avoid rotting. Standing water in a bilge is one of the greatest contributors to rotted wood. As the water evaporates the wood, which is porous, absorbs it and over time it causes rot. In fact, when the boat is stored for any length of time it's a good idea to open all hatches to allow air to circulate under the deck to keep the area dry. Some people even go so far as to put a small fan under the deck to circulate the air to enhance the drying.