Which one of the fish is not marine

Options

A. mackerel
B. sardine
C. hilsa
D. cyprinus

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks to identify which fish is not marine. Marine fish live in saltwater environments like oceans and seas, while freshwater fish live in lakes, rivers, and ponds.

2. **Defining Marine and Freshwater Fish**:
- **Marine Fish**: These fish thrive in saltwater environments and have adaptations to survive in high salinity. Examples include Hilsa, Pomfret, Sardines, and Mackerel.
- **Freshwater Fish**: These fish live in freshwater bodies with low salt content. Examples include Cyprinus (common carp), which belongs to the family Cyprinidae.

3. **Identifying the Options**: The question provides a list of fish, among which we need to identify the one that is not marine. The examples given in the transcript include:
- Hilsa (marine)
- Pomfret (marine)
- Sardines (marine)
- Mackerel (marine)
- Cyprinus (freshwater)

4. **Analyzing the Options**:
- Hilsa, Pomfret, Sardines, and Mackerel are all confirmed to be marine fish.
- Cyprinus, also known as common carp, is identified as a freshwater fish.

5. **Conclusion**: Since Cyprinus is the only fish mentioned that is not marine, it is the correct answer to the question.

### Final Answer:
**Cyprinus** (common carp) is the fish that is not marine.

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