Caught in mass in a clear lake that holds bass and trout.  

Cool looking fish, looks pike-ish from the stripes. 

possible rainbow. they have strips that look like mackerel.

I'm would second rainbow trout but its head shape tells me otherwise.

Not a baby anything, it's a minnow species.  Might be related to logperch.

1 hour ago, RMax said:

I'm would second rainbow trout but its head shape tells me otherwise.

I thought the same thing RMax.   It's Got to be a baby trout.....but after looking at the pic a few more times I thought the head didn't quite fit.  

 

The pond is north of Boston.   Super clear.  Bass.  Trout.  Perch.  All types of sunfish.   Never caught a pike or pickerel in there but heard they have been caught on occasion.  

I've seen these washed up on the bank before, at a lake exactly like you're describing, a clear trout lake. It's obviously not a bass or sunfish, definitely not an Esox, doesn't look like a juvenile trout. I agree with @webertime, must be a bait-fish species.

Hard to tell because you can't see the shape of the fins.  I don't think it is a baby.  Maybe an Eastern Banded Killifish?

 

http://gallery.nanfa.org/v/members/Nate+Tessler/nativenorthamericanfreshwaterfish/Fundulidae/Fundulus/diaphanus+diaphanus/Eastern+Banded+Killifish+_edit__+Currituck+Sound_+8-8-10_+NT.jpg.html

I think you got it Bass302.  Never heard of that type of fish until now.  

When my Grandparents were alive they owned a house in Cotuit Mass, on the Cape. We fished some ponds there and would seine our bait up before we went and that looks like what we called a chub; just a baitfish. Great bait with a hook up though the nose