Sardines/ Herrings
Clupeidae
Blennies
Blennidae
Triplefins
Tripterygiidae
Stargazers
Uranoscopidae
Brotulas
Bythitidae
Below is a heuristic guide for the typical fin layouts found in many fish families. Although certainly not exhaustive, it may prove useful as a quick initial pointer towards identifying an unknown fish.
Frogfish
Antennariidae
Cardinalfish
Apogonidae