Crayfish and silverfish belong to the phylum

Crayfish and silverfish both belong to the phylum Arthropoda, which is the largest and most diverse phylum in the animal kingdom [t1, t2]. Crayfish are aquatic crustaceans classified under the order Decapoda, characterized by their hard outer coverings and jointed appendages [t3, t4]. Silverfish, despite their name, are not fish but wingless insects belonging to the order Zygentoma [c1, t5]. They are terrestrial invertebrates known for their silvery appearance and fish-like movements [t5]. The phylum Arthropoda is defined by members having a rigid chitinous exoskeleton and segmented bodies with jointed legs [t2, t8]. While crayfish represent the crustacean group within this phylum, silverfish represent the insect group [t4, t9]. Other options like Amphibia (vertebrates), Mollusca (snails/clams), and Erachinida (misspelling of Arachnida) are distinct taxonomic groups [t9, t10].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > tro11ou ltn.ty*?. > p. 208
2. [2] https://en.wikipedia.org/wiki/Silverfish