🫧 Bubble Algae (Valonia)

Bubble algae (Valonia ventricosa and related species) are distinctive single-celled algae that form bright green, spherical bubbles on rocks and substrate. While a few bubbles are harmless, large infestations can be unsightly and spread rapidly. The key to control is careful removal without popping the bubbles.

📋 Quick Facts

🔍 Identification

Bubble algae is easy to identify:

• Spherical shape - Round bubbles like green marbles
• Shiny surface - Glossy, reflective appearance
• Bright green - Vibrant green color (sometimes darker)
• Attached at base - Anchored to rock by small holdfast
• Various sizes - From tiny (2mm) to quite large (20mm+)
• Often in clusters - Tend to grow in groups

⚠️ Why It's Problematic

• Spreads when popped - Contains millions of reproductive cells
• Rapid multiplication - One popped bubble can create dozens more
• Competes for space - Can overtake rock surfaces
• Aesthetically unpleasing - Detracts from tank appearance
• Can shade corals - Large growths block light

💊 Treatment Options

1. Manual Removal (Primary Method)

The most effective approach when done correctly:

• Do NOT pop bubbles - This spreads them dramatically
• Use tweezers to grip at the base
• Twist gently while pulling to detach holdfast
• Remove whole bubble intact
• Have siphon ready to catch any that accidentally pop
• Work during water change for easy siphoning

Tips for Successful Removal

• Use fine-tipped tweezers or hemostats
• Approach from the side, not top
• Grip the base where it attaches
• Slow, steady pressure - don't yank
• If bubble pops, immediately siphon the area
• Check for small bubbles hiding in crevices

2. Emerald Crabs (Best Biological Control)

Highly effective biological control:

• Mithrax/Mithraculus crabs eat bubble algae
• Add 1 per 20-30 gallons
• Very effective at preventing regrowth
• Will pop and eat bubbles (eating contents prevents spread)
• May become opportunistic with low algae (rare coral nipping)
• Best long-term prevention

3. Foxface / Rabbitfish

• Some individuals eat bubble algae
• Not guaranteed - varies by individual
• Require larger tank (75+ gallons)
• Bonus: eat other nuisance algae too

4. Rock Removal

• For heavily infested rocks
• Remove rock from tank
• Scrub with brush in bucket of tank water
• Pick off individual bubbles carefully
• Rinse before returning to tank
• Dispose of removed algae (don't return water to tank)

🛡️ Prevention

• Inspect new rock - Remove visible bubbles before adding
• Keep emerald crabs - Ongoing prevention
• Remove early - Don't let small infestations grow
• Maintain nutrients - Excess nutrients fuel growth
• Good flow - Bubble algae prefers calmer areas

❌ Common Mistakes

• Popping bubbles intentionally (causes massive spread)
• Leaving popped bubble contents in tank
• Ignoring small bubbles (they multiply)
• Rough removal that tears bubbles
• Not having emerald crabs for ongoing control

📚 Summary

Bubble algae is manageable with the right approach. The golden rule: never intentionally pop the bubbles. Careful manual removal combined with emerald crabs for ongoing control keeps most tanks bubble-free. If bubbles do pop accidentally, immediate siphoning minimizes spread. With patience and emerald crabs, bubble algae rarely becomes a serious problem.