Fish ID on graph screen?

[SpinLight]

Several times this year I have stopped on a spot and the screen would be full of thin black arches, spaced evenly apart from top to bottom on my Garmin screen. Not like a bait ball. This screen shot is similar to those I am talking about, but with some small colored arches also in this pic. Was fishing Lake Martin in AL where the most numerous bait fish are threadfin shad and blue back herring. Anybody know what kind of small fish these are on the screen?

[casts_by_fly]

how fast were you moving?  if you're truly stopped, then the screen will be 'stretched' lengthwise unless you also slowed down the scroll speed a ton.  It's hard to judge size and type in that regard.  Swapping to down imaging would give you a better view on size.

 

In this case, the schooling pattern is the full water column and possibly close packed.  Neither of which are going to imply bass.  No cover so open water schooling.  That says baitfish or trout to me.  One of the big lakes here gets trout dumped in at a few spots and they stay schooled up as they roam around near the stocking point for a while.

 

Also, you seem to have a good bit of interference on your unit (the vertical bars).  Not sure what your setup is, but that would drive me nuts on mine.

[WRB]

The above rely is spot on.

The screen display is 90% history only the far right 1/2” is currently inside your TD signal return cone. At 20’ depth the bottom cone size is about the width of your boat. 
Concerns are the high gain (power) setting and scroll speed. Notice the current sonar returns are mis shaped, the upper 1/3 or 5’ are very strong (red) the balance are weak. To me this means the water column has bubbles or debris along with faster moving smaller fish.

As noted you have interference in verticle lines.

Is your unit manual settings or factory default? If manual adjust the gain a tick to remove the clutter and interface lines. If you are idling at walking speed slow down scroll speed a little until the right 1/2” of the screen has sharp images.

Bottom line I believe your screen shot indicated debris ghosts from too high gain for the water condition and depth.

Tom

PS, Fish ID is a term used for fish Icon display.