Standard Metapuzzle

Is this a fake answer?

You notice a fifth crate, which had been hidden behind the others. It has a label attached to it, and another keypad-enabled lock.

Inspecting the final crate reveals a blanked out flag for the Central African Republic.

Reviewing the answers needed to unlock the previous crates reveals colors that match the horizontal bands of this flag.

Puzzle	Answer
Artwerk	BACHELOR BLUE
Primitive Markings	WHITE MORRIS
Math Test	GREEN SHINER
Ape Crossword	YELLOW ANGEL

Using the color in the answer as a guide for where to place the second word, writing these answers into the band of the flag with the center letter(s) falling in the red band is shown below.

Reading down the middle gives the word HERRING, which when combined with the color of the band being RED, gives the final answer of RED HERRING.

Inside the Crate

You unlock the final crate, and as it opens you are bombarded with one of the most vile, noxious odors you've ever had the displeasure of smelling. You look closer - while holding your breath, of course - to find that the crate is full of fish. Small, shiny fish... herring? You shine a light on them and notice they're a crimson hue. Literal red herring!? Hmm…

You start to turn away in defeat, frustrated at having spent all that time solving a complex cipher just to end up face to face with a bunch of rotten old fish, when you notice something in the corner of your eye. A greenish glow that stands out amidst the red scales. It seems to be coming out of a herring’s slightly open mouth. Do you reach into the fish's mouth to investigate further?