Why are clingfishes no longer classified as paracanthopterygians?

Clingfishes are no longer classified as paracanthopterygians because modern biological classification now identifies them as perciform fishes.1

While they were once grouped within the superorder Paracanthopterygii, ongoing scientific study into the interrelationships of these fishes has led to reclassifications. The superorder itself remains a provisional grouping, as the evolutionary connections between its members are not yet fully established. Consequently, as research continues, the composition of such groups is subject to change based on new morphological and molecular data.12