I used to have that setup and I did use a bucket to fill when using it for a livewell. 
I since stared using a cooler as a livewell when needed. 
 
Early on I made the mistake of using that space as a fishbox when striper fishing. 
When I drained the box, the large scales of the stripers blocked up the drain pipe that runs under the fuel tank compartment...friggin' disaster! 
 
I use that space for storage now (4 gallon buckets with lids). Also, I cut the bottom out and I have a 2nd bilge pump in there
		 
		
		
		
		
		
		
			
		
		
		
		
		
	
	 |