Diagonal lines on fish finder

I'm still learning to read my fish finder. I was recently in about 12 fow, trolling on slow speed, and saw many diagonal lines going from lower left to upper right. What was I seeing? I didn't take any pics.

Not seeing pics, it could be interference or fish swimming fast under boat. Your jig will also look like a streak while falling to bottom. When you spook fish they move fast enough to look like lines. Hope this helps

Not sure, but my guess is trees, especially if you're moving.

small fish swimming

Were you on a school of shad? If there are fish coming up from the bottom to feed on the shad, it will look like a diagonal line. A regular sonar reads from right to left, so whatever is on the far right is what is directly under your transducer, or within the cone. So if an object is at say, 12 feet when it starts to read that object but it is moving vertically or swimming to the surface, there will be a diagonal line marking the path. Was that as clear as mud? Having said all that, it could've been anything. Weeds, limbs hard to say w/o seeing it.

I have seen diagnal lines while sitting on top of brush before. I asked a guide at the marina what he thought it was since I could only see it on one top. He knew the top and said it was bream. I went back with some crickets and loaded up.
DP

It is fish, cover, or your jig, you can replicate the same line by lifting or lowering your jig near your transducer.

Decrease the sensitivity just a little and they will go away. I know exactly what you are talking about.

I'm assuming you are not leaving your sensitivity on "AUTO"

Air bubbles coming off the bottom probably.

I see this in hot summertime. I think it is small fish that swim up to the shade of the boat.

Thanks for all of the input. If I see it again, I'll take pics. I've only seen it that one time, so who knows when I'll see it again.

It is air bubbles coming up from the bottom of the lake.