Because fly placement is critical, it’s probably more important to see permit than it is to see any other flats species you’ll stalk.
Contrary to rumor, permit are not harder to see than other fish; they are just different. Standard advice is to look for the darkest part of the fish — their coal-black, forked tails. This is especially true when trying to spot smaller permit. But the longer you pursue permit, the more you will begin to look for the whole fish. Permit are generally larger than bonefish; yet they typically frequent darker-bottom flats and don’t cast a telltale shadow as often.
Head-on, however, the dark band that runs down their back from just behind their head to their tail is a dead giveaway. This is why a permit can seem to suddenly appear and then disappear as he first turns toward and then sideways to the angler. Also, despite previously published claims to the contrary, permit do in fact mud, and their muds are especially visible when they hold in current on dark, grassy bottoms or move across the current on a favorite flat, leaving short “smoke trails” each time they dig into the bottom.
“Nervous water” is a giveaway too, especially places where permit are comfortable high up on a flat. Disturbances on the surface may not always be made by permit–but sharks and rays can both have permit following them, so any nervous water is worth checking out.
And of course you’ll sometimes see a permit tail or tail tip, especially when a permit is nose-down in shallow water. On especially calm days, permit tail tips often pop up when the fish are “floating” or hanging in current, as they look for crabs and shrimp on the surface.