Since the tags encompassed by "fish" are somewhat unorganized, I was thinking in a way for sort them and I believe that would be interesting to do so using the pisces superclasses (considered classes by some authors).

• agnatha (jawless fishes).
• chondrichthyes (cartilaginous fishes).
• osteichthyes (bony fishes).

Exemplification:

• fish
• bony_fish¹
• barracuda
• cartilaginous_fish¹
• shark
• agnathan
• lamprey

¹ Easier to type when compared with the actual names.