Firstly lets start with -
1. For the 2.5 acres how many pounds and specific numbers of each fish species that are harvested from the pond each year?
2. What is the weed community structure / density % area with what type of submerged weed/s in this pond?
3. What is the usual water clarity/visibility ?
4. If you do not have that information then good advice from here is weakly based.