Alligator Reef

Alligator Reef sits off Islamorada in the Florida Keys, marked by a lighthouse built in the 1870s on the reef itself, named after the USS Alligator, a naval schooner that wrecked there in 1822. The reef is a shallow spur and groove coral formation typical of the Keys reef tract, with a maximum depth of around 21.3 metres and a bottom made up of reef structure, and it is rated a beginner dive overall. Nurse sharks are a regular sight here, and divers have also reported barracuda and grouper on the reef. It remains a popular stop for dive operators running out of Islamorada, with conditions generally mild though visibility and current can vary with weather and tide.

Confirmed by our research team, reported by independent divers, or observed nearby via iNaturalist — each entry is labelled with its source.

• Caribbean Bluehead WrasseThalassoma bifasciatumReported here · unconfirmed
• Bicolor DamselfishStegastes partitusReported here · unconfirmed
• Slippery DickHalichoeres bivittatusReported here · unconfirmed
• Redband ParrotfishSparisoma aurofrenatumReported here · unconfirmed
• Yellowhead WrasseHalichoeres garnotiReported here · unconfirmed
• Brazilian Ocean SurgeonfishAcanthurus bahianusReported here · unconfirmed
• Clown WrasseHalichoeres maculipinnaReported here · unconfirmed
• Striped ParrotfishScarus iseriReported here · unconfirmed
• Atlantic Blue TangAcanthurus coeruleusReported here · unconfirmed
• White GruntHaemulon plumieriiReported here · unconfirmed
• GrouperGrouperReported here · unconfirmed
• Nurse sharkNurse sharkConfirmed present · 2 independent sources
• BarracudaBarracudaReported here · unconfirmed