This puzzle is a combination of a Touching Slitherlink and an Aquarium. The Touching Slitherlink loop divides the grid into regions for the Aquarium.
Touching Slitherlink: Draw a line along the edges of some cells to form a single non-intersecting loop. Clues inside the grid indicate the number of times the loop visits the set of edges and vertices adjacent to the clued cell.
Aquarium: Fill some cells with water. If a cell is filled with water, all other cells within the same region that are in the same or a lower row have to be filled with water as well. Clues outside the grid indicate the number of water cells in the corresponding row or column.
Here is a 6x6 example puzzle: