Overview
The Blue-Ringed Octopus (Hapalochlaena maculosa) is a do not keep saltwater species known for its tan-yellow, bright blue rings (warning) coloration. EXTREMELY venomous. Bottom to Surfaces.
Origin & Appearance
Origin: Indo-Pacific.
Colors: Tan-Yellow, Bright blue rings (warning).
Body Shape: Cephalopod (soft-bodied). Typical adult dimensions: 20.0 x 16.0 x 8.0.
Sexual Dimorphism: Moderate; males have hectocotylus arm.
Tank & Water Requirements
| Min Tank Size | 20 gallons |
| Temperature | 72–79°F |
| pH Range | 8.1–8.4 |
| Water Hardness (GH) | dKH 8-12 |
| Bioload | high |
| Oxygen Demand | high |
| Plant Safe | yes |
| Aquarium Position | Bottom to Surfaces |
Behavior & Activity
Crawling reef walker; walks on arms over surfaces; blue rings flash bright as warning before lethal bite; jet swimming
Speed: 55/100Aggression: 5/10nocturnal
Breeding
Terminal; dies after breeding
Common Diseases
💊 Senescence after breeding💊 escape artist
Expert Notes
EXTREMELY venomous; lethal bite; DO NOT KEEP