Fishy Fog is an ability exclusive to Dragon Quest VII, learned by reaching rank 6 of the Gripevine (Class).
Function
When used, the fog targets all enemies & allies and prevents status changes from taking place for 4~7 turns. In essence, Fishy Fog is the skill equivalent to The Great Leveller and as such a sort of preemptive Disruptive Wave.
Because The Great Leveller is exclusive to the Hero, Fishy Fog is the only way for other characters to gain a similar ability.