Blue Runner
Blue Runner (Caranx crysos) is a saltwater species. The first thing to check: a small dark spot on the rear edge of the gill cover, and no dark blotch at the base of the pectoral fin. The look-alike to rule out is Crevalle Jack: crevalle have a steep, blunt forehead and a second black blotch at the base of the pectoral fin; blue runners have neither.
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| Scientific name | Caranx crysos |
|---|---|
| Also called | hardtail, hardtail jack, runner |
| Water | Saltwater |
| Group | Jack |
| Temperature | Common between 70 and 86 °F. |
How to identify a Blue Runner
- A small dark spot on the rear edge of the gill cover, and no dark blotch at the base of the pectoral fin.
- A gently sloped forehead on a slim, streamlined body — nothing like the blunt vertical head of a crevalle.
- Bony scutes along the rear lateral line, and a tail that is often dusky to olive rather than yellow.
If you would rather not work through a key on a wet deck, photograph the fish and let the app name it — you get the common and the scientific name back, and the record is filed before you release.
Fish it is mistaken for
| Species | How to tell them apart |
|---|---|
| Crevalle Jack | Crevalle have a steep, blunt forehead and a second black blotch at the base of the pectoral fin; blue runners have neither. |
| Horse-eye Jack | Horse-eye have a much larger eye and a distinctly yellow tail, and grow considerably bigger. |
Side-by-side comparisons
Read the full entry for Crevalle Jack and Horse-eye Jack.
Where it lives
Atlantic and Gulf coasts, around nearshore structure, reefs, piers and buoys, and one of the most widely used live baits in the region.
Temperature
Common between 70 and 86 °F.
The conditions that matter
Blue runners school hard around structure on moving water and are usually the first thing that shows on a chum slick. Because they are as often bait as target, knowing them on sight matters — a livewell of hardtails is what turns a slow day offshore into a viable one.
Global Fishing League records 18 weather and water readings against every catch automatically — tide stage, barometric pressure, water temperature, salinity, dissolved oxygen, chlorophyll, swell, current, moon phase and more, taken at your GPS position at the moment you log the fish. Over a season that turns a hunch about blue runner into a pattern you can read.
See every reading recorded with a catch, or the guides to what each reading means.
Size limits, bag limits and seasons
Size limits, bag limits, slot limits and seasons are set by your state wildlife agency — and for many offshore and migratory species by federal regulators — and on many waters they differ from the statewide rule. They also change between seasons. Check the current regulations for the exact water you are fishing before you keep a fish — we do not republish limits here, because a number that is a season out of date is worse than no number.
What the app does do is make your side of it accurate: every catch carries a length measured from the photograph, a GPS position and a timestamp, exportable if you ever need to show your work for a tournament or a record claim. It is also what a Global Fishing League entry is built from — a record that verifies itself, without publishing where you caught the fish.