How can one distinguish between suspended fish and horizontal branches around submerged timber?  I regularly fish a lake with a lot of submerged timber and the fish are usually near it.  It would speed up my search tremendously if I could use my sonar to locate them and then continue the pattern throughout the lake.  Also, I just want to know if it's possible to tell the difference.  I have an Eagle Fishmark 320, BTW.

I may be wrong but I think the 320 lacks the power and resolution to distinguish between the 2.

I've started calling my fish finder a 'structure finder'.  I use it to find depth and structure and just assume the fish are there.

BTW I have a FishMark 320.  This is my first unit and I've used it twice.  So far I can't tell if the blobs are fish are something else.  I don't think this has to do with the unit, it's my lack of experience.

Your eagle should be able to see fish in tree structure, but a higher power unit with higher resolution would make that easier. It will depend how close the fish are to the structure if the unit will be able to tell the difference between the 2.  The depth the structure is in will help as well.  The shallower the water the smaller area you see at the bottom.  A 20 degree cone angle at 15 feet will only see about a 5 foot circle at the bottom.  

I want a hummingbird SI.  It seems to be easier to distinguish what is really on the bottom.

once you use SI everything else is just another depth finder