池塘里的鲑鱼主要以这些微小的桡足类动物为食。

The salmon in the pond mainly feed on these tiny ___copepods.

这些寄生桡足类动物附着在鱼身上，影响了它们的健康。

These ___copepods attach to the fish and affect their health.

科学家通过研究河流中的桡足类动物来判断水质是否健康。

Scientists study ___copepods in the river to determine if the water is healthy.