To effectively see fish on your Garmin fishfinder, you need to understand how sonar works and how to interpret its display. While your unit can show fish as recognizable symbols, learning to read the raw sonar data—often displayed as arches—provides the most accurate and detailed information.
Understanding Your Garmin Fishfinder's Display
Your Garmin fishfinder uses sonar to detect objects underwater, including fish. A transducer sends sound waves into the water, and when these waves hit an object, they bounce back to the transducer. Your unit then processes these echoes and displays them on the screen.
There are two primary ways fish are depicted:
- Fish Arches: These are the most accurate representation of fish. An arch forms when a fish enters and exits the sonar cone. As the fish moves through the cone, the distance to the fish changes, creating a curved line on the display.
- Fish Symbols (Fish ID): Many Garmin units offer a "Fish ID" feature that interprets sonar returns and displays them as graphic fish symbols. While convenient, these symbols are an interpretation and might not always be perfectly accurate, potentially missing smaller fish or misidentifying debris.
Optimizing Your Garmin Settings to Spot Fish
To improve your chances of seeing fish, whether as arches or symbols, adjusting your unit's settings is crucial.
Key Settings to Adjust:
- Gain/Sensitivity: This controls how much detail your unit displays.
- Increase gain in clear, deep water to pick up weaker signals.
- Decrease gain in murky or shallow water to reduce clutter and false readings.
- Tip for arch interpretation: When you have fish symbols turned off to better interpret raw sonar data, try setting the gain up to approximately +2 from its default or auto setting. This often makes it easier to discern potential fish returns.
- Depth Range: Ensure the depth range is set appropriately for the water you're fishing. Auto-range works well, but manual adjustment can help focus on specific depths.
- Frequency:
- High Frequencies (e.g., 200 kHz, CHIRP High): Provide better detail and target separation, ideal for shallower water and identifying individual fish or baitfish schools.
- Low Frequencies (e.g., 50 kHz, CHIRP Low): Penetrate deeper water, offering a broader cone angle, which is good for covering a larger area in deep water but with less detail.
- Scroll Speed: This determines how quickly the sonar history moves across your screen.
- Faster speeds provide a more real-time view, which is good when moving quickly.
- Slower speeds stretch out the sonar history, making it easier to see the shape of arches and identify patterns, especially when drifting or stationary.
- A-Scope (Amplitude Scope): This feature often appears as a real-time vertical flasher on the right side of your screen. It shows the strength of returns in real-time, helping you differentiate between a weak return (smaller fish or bait) and a strong return (larger fish or structure) directly under the boat.
- Color Palette: Experiment with different color palettes. Some offer better contrast, making it easier to distinguish between different types of returns and identify fish arches. Typically, stronger returns are depicted with hotter, brighter colors.
Using Split-Screen Views
Many Garmin units allow for split-screen views, which can be incredibly helpful for fish finding.
- Traditional Sonar + Zoom: This combination is powerful. You can run your main sonar screen and, for better visibility, use a split-screen zoom view on the side. This feature magnifies a specific depth range, making it significantly easier to pick out fish arches and differentiate them from structure or bait. Even with optimal settings, keep in mind that your unit may not always display perfect arches.
- Traditional Sonar + DownVü/SideVü: If your unit has Garmin's DownVü (clear, photographic-like images directly below your boat) or SideVü (images to the sides of your boat), combining these with traditional sonar provides a comprehensive view of the water column and surrounding areas. Fish will often appear as bright dots or blobs on DownVü/SideVü.
Interpreting What You See
- Identify Baitfish Schools: Baitfish often appear as dense clouds or clumps on your sonar. Larger predator fish are frequently found on the edges of or directly below these bait balls.
- Look for Structure: Fish love structure (reefs, wrecks, fallen trees, drop-offs). Your sonar will display these as defined shapes. Look for fish arches or symbols near these structural elements.
- Thermoclines: These are layers of water at different temperatures that can appear as distinct lines on your sonar. Many fish species will hold above, below, or directly in thermoclines.
Table: Quick Reference for Fishfinder Settings
| Setting | Purpose | Optimal Use Case |
|---|---|---|
| Gain | Controls sensitivity to sonar returns | Adjust higher for deep water, lower for shallow/murky water |
| Frequency | Determines sonar beam characteristics | High for detail (shallow), Low for depth (deep) |
| Scroll Speed | How fast sonar history moves across screen | Faster for moving, Slower for stationary/drifting |
| Fish ID | Toggles graphic fish symbols on/off | On for beginners, Off for advanced arch interpretation |
| Zoom | Magnifies a specific depth range | Essential for detailed fish identification |
By understanding these principles and actively adjusting your Garmin's settings, you'll significantly improve your ability to locate and identify fish.
For more detailed information and specific unit instructions, you can consult your Garmin owner's manual or visit the official Garmin Support Center.
