Personally, B&T .... I'd probably never even turn the 2d sonar on. Fish symbols lie as the 2d sonar processor cannot distinguish between a fish & a waterlogged object not connected to the bottom.
Fish arches are only accomplished when this happens:
... and the "arch" is usually only defined if the fish travels through the middle of the cone. Otherwise it can show up as a partial arch or a blob with a rounded top.
I have a Elite 5DSI, which has no 2d sonar capabilities. And that's after having 2d units for decades. But, to be honest, I don't miss the fish symbols or the pixelated blobs that were supposed to be showing the bottom cover ... but, left it up to you to figure out what the heck was showing on the screen.
Now that I have DSI ... I can get a picture quality image of exactly what's down there, and if I want to see "fish" then I "zoom" the screen & look for the little white blotches. I'd show you some screenshots of those white "fish" blotches, but whenever they've come on my screen I've been too busy watching my rods or setting the hook, to bother taking the time to take a screenshot
I'd much rather see this :
than I would a multicolored blob that "could be" anything from a bush, to a tree, to a hump on the bottom, to a heavy ball of baitfish ... like a 2d sonar shows.
That's my ... your mileage may vary.
... cp