From your experiments, you conclude that the mosquitofish are already
consuming too much oxygen from the pond. Any added goldfish are
suffocating.
You have estimated that the Elodea currently in your pond produce 22.8 mL of
oxygen per hour.
A2 gram goldfish will need 6.2 mL oxygen per hour. A small 0.5 gram
mosquitofish will need 2.2 mL of oxygen per hour.
Determine how many mosquitofish and goldfish the pond can support.