Don't confuse these elongate fishes!!

These three families are often mistaken by Ichthyology students on Lab practical exams.

In the photo on the top the fish the long dorsal and anal fins run confluent with the caudal fin.

In the second photo the fish has a larger pectoral fin. The families are closely related; however the fish tend to be larger and attain lengths of 150 cm.

The fish in the bottom photo have a very long and well spined dorsal fin that runs the entire length of the body and if they have pelvic fins they are very small. The dorsal fin is twice as long as the anal fin.

In what families do these fish belong?