Blue Seafan

Acalycigorgia sp

Habitat & Distribution :  Indo-Pacific Ocean

Diet: Plankton

Size: 20 - 40 cm

Lifespan: 1 - 2 tahun

Description

The Blue Sea Fan is a type of non-photosynthetic soft coral that features a striking contrast of colors and a beautiful branching structure. This coral forms intricate, lush, and delicate fan-like branching networks, typically reaching heights between 20 and 40 centimeters. Its primary skeleton is supported by a flexible central core made of gorgonin protein, which is commonly orange, red, or yellowish in color. The stem is covered with round, fuzzy polyps of a deep blue or vibrant purple hue that closely resemble blueberries. These polyps are non-retractile, meaning they cannot fully pull back into the skeletal stem; instead, they can only contract and fold inward toward the body surface of the coral when disturbed.

Behavior

The behavior of the Blue Sea Fan centers on how its polyps react to water currents for feeding and self-defense. As a passive suspension feeder, this coral opens its blue polyps fully to catch microplankton carried by the current, then closes them for a few seconds to digest the food. In the wild, its colonies always grow perpendicular to the direction of the main current to maximize nutrient capture. Conversely, if it detects a threat, or if the surrounding water current is either too calm or too extreme, the polyps will automatically contract and fold inward to protect itself.

Reproduction

The reproduction of the Blue Sea Fan occurs through both sexual and asexual methods. Sexually, this coral engages in broadcast spawning—releasing eggs and sperm en masse into the water column following lunar cycles—where fertilization produces planula larvae that drift and eventually settle on new substrates. Asexually, they multiply through budding to expand the colony, as well as through fragmentation, which happens when broken branch pieces caused by strong currents or intentional cutting reattach to rocks and grow into new, genetically identical colonies.

Communication & Perception

The communication and perception of Acalycigorgia sp. rely on a simple nerve net and chemical interactions because they lack a brain. This coral perceives its environment using chemoreceptors and mechanoreceptors on its polyps to detect food, physical touch, and changes in water currents. Communication between polyps within a single colony occurs via internal electrical signals; if one polyp is touched or attacked, a danger signal propagates rapidly, causing neighboring polyps to contract simultaneously for protection. Additionally, they engage in external biocommunication by releasing chemical compounds into the water to defend their territory from other corals.

Predator(s)

Gastropods (snails), nudibranchs (sea slugs), and certain species of fish.