Fish jumping into the filter compartment in biocube

[Ian]

I had the same problem when I got mine. The solution came in 2 parts; first be careful not to fill too high or the waterfrom the front of the tank can cascade over the top of the divider into the back bypassing the filter as well as making it easy for fish to swimm into the back, second I went out and got some eggcrate from home depot and glued in a piece the was the entire width of the tank and extended up to meet with the lid. The 2 steps have ended the issue completely.