Trout pong exploration?

Sure you can. The first year you begin with 3,000 NOW (Year 1) and you lose 600 (20% loss) at the beginning of NEXT = 2400 but gain 100 NOW. So you can say: NOW -20% + 100 = NEXT. This yields a net loss of 500 trout a year. NOW - 20% +100 = NEXT (Year1). NEXT - 20% NOW +100 NEXT(Year2) = NOW, then continue as it is a steady loss outweighing the new. NOW - 20% NOW +100 NEXT = NOW - 20% NOW + 100 NEXT = NOW etc,etc.