unsuccessful install nimrod-mode

try.el

; what I have in /emacs.d/init.el

(require 'package)
(package-initialize)
(add-to-list 'package-archives
  '("melpa" . "http://melpa.milkbox.net/packages/") t)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; what I did to install nimrod-mode
; M-x package-install nimrod-mode
;
; result
; M-X nimrod-mode [No match]
; no highlight of .nim file
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; what I did previously
; M-x package-install fish-mode
;
; result
; M-X fish-mode succeed (highlight current buffer according to fish syntax) 
; highlight of .fish file
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;