How to Identify Fish While Diving

Identifying fish underwater is a skill you build dive by dive. Start with silhouette and behaviour, then refine with stripes, spots and fin shapes once you are neutrally buoyant and not chasing the animal.

Build a repeatable ID workflow

1. Silhouette first — Is it elongated like a barracuda, oval like a damselfish, or ray-shaped?
2. Habitat — Sand, reef wall, seagrass or open water narrows candidates quickly.
3. Key marks — Count bars, note eye stripes, and check whether the caudal fin is forked, rounded or lunate.
4. Photo when safe — A side-on image with the whole body in frame is worth more than a blurry chase shot.

Common mistakes

Colour shifts under ambient light. A red fish may look brown at depth. Do not rely on colour alone. Location matters: Mediterranean groupers and Red Sea anthias live in different assemblages.

Tools that help after the dive

Use Scuba Steve’s fish identification app to compare lookalikes from your photos. Cross-check with destination guides such as Red Sea or Medes Islands, and read species pages like lionfish or dusky grouper.

Treat every AI or app suggestion as a shortlist, not a museum label. Verify unusual records with a local guide or field book.