The rules for this puzzle originate from Phistomefel's Fillomino Aquarium.
This puzzle is a combination of a Fillomino and an Aquarium.
Fillomino: Divide the grid into regions of orthogonally connected cells. Two regions of the same size may not share an edge. Clued cells must belong to a region containing the indicated number of cells.
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.