There is one very easy way - Grab an egg raise in the the containment then once it's hatched simply go into the containment and scan the docile crashfish.
Alternative: Between West and NW from starting point/centre of Map, south of the crashed aurora there is a large bit of rock that nearly rises to the surface only a few metres away, in a hole leading inside the top of the rock is 2 crashfish but they're spawned horizontally. One will immediately charge towards you but the other won't because it's facing the opposite direction and because the plant and it is fancing horizontally when it should normally be facing upright against a surface, the bottom of the crashfish is sticking out of the base of the plant, if you very slowly approach from behind then you can successfully scan it.
Happy Scanning!