<p dir="ltr">FASTA file with the sequences for amphibian, fish and reptile species registered to occur in Mexico City, functioning as a custom reference database for the 12S-V5 metabarcoding library. The Alt12S primer pair was developed for the project, yielding amplicons that contain the MiFish and 12S-V5 markers. Sanger sequences were obtained through DNA extractions from preserved tissues (obtained through the project's collaborators) using the QIAGEN DNeasy Blood & Tissue kit. The processing of the sequences (including <i>de novo</i> assembly) was done using Geneious Prime. Sequences were used during the Taxonomy Assignment step of the bioinformatic pipeline using Python packages <i>BLAST+</i> and <i>BASTA</i>.</p>