Insects vastly outnumber fish worldwide. While precise totals vary by source and method, current best estimates place insect species by the hundreds of thousands to several million, whereas fish species are typically counted in the low tens of thousands. This means there are far more insect species than fish species. Key points
- Insects: The most species-rich group of animals. Estimates commonly cited place insect species well above 1 million, with some projections around 3–5 million depending on undiscovered diversity and taxonomic work. This makes insects the dominant majority of animal diversity by species count. [web results commonly referenced in summaries of biodiversity]
- Fish: Fish diversity is substantial but much smaller in species count, generally estimated around 30,000 living species. This places fish far below insects in total described species. [web results commonly referenced in biodiversity summaries]
If you’d like, I can pull up the latest specific sources and retrieve exact figures from reliable institutions (e.g., major biology or biodiversity databases) and provide a concise side-by-side citation-backed comparison.