
Kelleston Drain
Speyside · Trinidad and Tobago
Drift dive off the southern flank of Little Tobago, 3 km east of Speyside, ending at the largest documented brain coral colony on Earth — a boulder brain (Colpophyllia natans) roughly 3 m tall and 5 m across, estimated to be more than two centuries old. The reef slopes from 18 m down past 40 m through forests of gorgonians, sea whips, and barrel sponges fed by nutrient rich currents pushing up from the Guiana plume.
Conditions
Depth
18 to 40 m
Advanced depths
Current
Often strong
Can pick up on the edge
Visibility
10 to 20 m
Clearest in the calm season
Water
26 to 30°C
Tropical 3mm or shortie
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 26 | 26 | 26 | 27 | 27 | 28 | 28 | 29 | 29 | 28 | 27 | 26 |
| Vis (m) | 20 | 20 | 20 | 20 | 20 | 15 | 10 | 10 | 10 | 10 | 15 | 20 |
| Current | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Strong | Strong | Strong | Moderate | Moderate | Moderate |
Your chances of seeing each animal
Boulder brain coral
Last confirmed May 15, 2026 · 130 records
Almost always
Nearly every dive
Ocean triggerfish
Last confirmed Feb 11, 2025 · 1 records
Likely
About 6 in 10 dives
Southern stingray
Last confirmed Jun 21, 2026 · 4 records
Likely
About 6 in 10 dives
Nurse shark
Expected
Known here, not yet in recent logs
Caribbean reef shark
Expected
Known here, not yet in recent logs
Tarpon
Expected
Known here, not yet in recent logs
Manta ray
Expected
Known here, not yet in recent logs
Gear