Entry in progress—B.P.
 
(Oxford English Dictionary)
fish-wrap adj. and n. N. Amer. colloq. (depreciative) (a) adj. of, relating to, or designating a low-quality publication, esp. a newspaper; (b) n. ephemeral printed matter which lacks (lasting) worth (considered as useful only for wrapping fish).
1964 S. MARTINELLI Let. 5 Aug. in C. Bukowski & S. Martinelli Beerspit Night & Cursing (2001) 306 Wax Wrath [i.e. Kenneth Rexroth] knows all this too—and often employs it in his *fish-wrap chats—as this reader most certainly understands.
1966 Independent (Long Beach, Calif.) 28 Feb. 1/6 (heading) Fish-wrap ages nearly as fast as fish. A new art magazine..will participate in the ‘autodestruction’ school by treating the pages..with a chemical ‘so that copies will disintegrate..in about four weeks’.
1991 M. ATWOOD Wilderness Tips 223 A year from now it’ll all be fish-wrap.
2001 Village Voice (N.Y.) 25 Dec. 114/3 Quoyle installs himself at the local fish-wrap newspaper.
   
fish wrapper n. N. Amer. colloq. (depreciative) a newspaper (cf. fish-wrap adj. and n. at Additions).
1910 C. E. MONTAGUE Hind Let Loose i. 11 ‘The *fish-wrapper’, a title exchanged..by two standard-bearers of our culture in the press of the Far East.
1940 Oakland (Calif.) Tribune 9 Jan. 21/1 The story of those Hawaiian hula dancers—a publicity stunt as flagrant as it proved illegal—was announced exclusively in his fish-wrapper!
2003 Philadelphia Inquirer 16 May A26/2 Blair wasn’t working for just any old fish wrapper but for the most venerated newspaper in the country.