The fish that swims vertically :-

Options

A. Scoliodon
B. Hippocampus
C. Exocoetus
D. Syngnathus

Answer

To solve the question "The fish that swims vertically," we will analyze each of the given options step by step.

### Step-by-Step Solution:

1. **Identify the Options**: The options provided are:
- Option 1: Squalidon
- Option 2: Hippocampus
- Option 3: Exocetus
- Option 4: Synconeptus

2. **Evaluate Option 1: Squalidon**:
- Squalidon is known for its elongated and spindle-shaped body.
- It is tapered at the ends and has a body structure that allows it to swim in a lateral manner, not vertically.
- **Conclusion**: This option is incorrect.

3. **Evaluate Option 2: Hippocampus**:
- Hippocampus is commonly known as the seahorse.
- Seahorses are unique as they swim in a vertical position, often with slight forward and backward inclinations.
- **Conclusion**: This option is correct.

4. **Evaluate Option 3: Exocetus**:
- Exocetus, also known as the flying fish, has adaptations that allow it to glide above the water surface.
- However, it does not swim vertically; it swims horizontally and can leap out of the water.
- **Conclusion**: This option is incorrect.

5. **Evaluate Option 4: Synconeptus**:
- Synconeptus is another type of fish that does not swim vertically.
- It has a body structure that is not suited for vertical swimming.
- **Conclusion**: This option is incorrect.

6. **Final Conclusion**:
- After evaluating all options, the only fish that swims vertically is **Hippocampus** (the seahorse).

### Final Answer:
The fish that swims vertically is **Hippocampus**.