Question: asked about death of fishes due to low oxygen demand
Answer: told him to do the following things - 
1. provide oxygen tablet (oxyprin) and apply as prescribed for the tablet. 
2. cut the trunk of the banana tree in one or two part in round shape and apply it.
3. apply potassium permanganate or potassium crystal for 25gm in 5 kotha in one day interval.
4. reduce stocking density or transfer to another pond.