Bubble algae

Care at a glance

Bubble algae form glossy green spheres that sit on the rock like droplets and can grow to a few centimetres across. Each of those spheres is a single giant cell, which makes it one of the largest single-celled organisms in the world.

Never burst it inside the aquarium: rupturing releases spores that spread across all your rock. Remove the bubble carefully and whole, preferably along with the piece of rock beneath it, or add emerald crabs, which nibble the bubbles and help keep the plague in check.

Natural predators

• Emerald crabMithraculus sculptus

Related species

• Red mangroveRhizophora mangle
• Mermaid’s fanUdotea sp.
• Shaving brush plantPenicillus capitatus
• Dragon’s breath algaeHalymenia sp.
• Sea lettuce (ulva)Ulva lactuca
• Sea grapes (ornamental macroalgae)Botryocladia sp.