Thanks ! :)
If you're refering to the blue colors used for the water in the preview screenshots, they're not exactly sprites. They're just background colors with white particles spawned randomly (it should be pretty easy to replicate in most engines without needing specific sprites ;) )
If you need the exact colors the hexcodes for each of them are : #50b9eb, #354ab2 & #1d1a59
Hope that helps !