So first, you need to find the volume of the tank. 25*30*39=29250 cubic cm. If each fish requires 10,000 cubic centimeters of water, you will need to divide 29,250 by 10,000. That would equal 2.925. So, even though it rounds up to 3, the 3rd fish would not have enough space. That leaves us to say that the tank can only hold 2 fish.
