đĒą Bristleworms
Bristleworms are segmented polychaete worms commonly found in reef aquariums. They're often vilified by hobbyists who discover them crawling on rocks at night, but the truth is that most bristleworms are beneficial members of your cleanup crew. Understanding which types are helpful versus harmful is key to managing these creatures appropriately.
đ Quick Facts
| Type | Polychaete worms (Errantia) |
|---|---|
| Appearance | Segmented worms with bristles, pink/red/brown |
| Severity | Low - Mostly beneficial, some exceptions |
| Common Entry | Hitchhiker on live rock |
| Treatment Difficulty | Easy - Usually no treatment needed |
đ Identification
Common (Beneficial) Bristleworms
Most bristleworms in aquariums are harmless scavengers:
- Size: Usually 1-4 inches, rarely larger
- Color: Pink, tan, or reddish-brown
- Bristles: White, visible along body segments
- Behavior: Nocturnal, hide in rockwork during day
- Diet: Detritus, uneaten food, dead organisms
Fireworms (Problematic)
Fireworms are a specific type of bristleworm that can be harmful:
- Size: Can grow 6-12+ inches
- Color: Often more colorful (red, orange with white tufts)
- Bristles: Longer, more prominent, break off easily
- Body: Flatter, wider than common bristleworms
- Behavior: More aggressive, may attack corals or clams
- Sting: Bristles cause painful irritation in humans
Telling Them Apart
| Feature | Common Bristleworm | Fireworm |
|---|---|---|
| Size | 1-4 inches typical | 6+ inches common |
| Shape | Cylindrical | Flattened |
| Bristles | Short, close to body | Long, feathery tufts |
| Color | Pink/tan/brown | Red/orange with white |
| Aggression | Scavenger only | May attack live tissue |
â Benefits of Bristleworms
Most bristleworms are valuable tank inhabitants:
- Detritus removal - Consume rotting organic matter
- Uneaten food cleanup - Eat food that fish miss
- Carrion disposal - Quickly consume dead animals
- Substrate aeration - Burrow through sand, preventing dead spots
- Nutrient export - Convert waste into biomass
- Indicator species - Large populations indicate overfeeding
â ī¸ When Bristleworms Become Problems
- Massive population - Indicates overfeeding or excess detritus
- Fireworm species - May attack corals, clams, or anemones
- Stinging - Bristles can irritate skin during tank maintenance
- Attacking stressed animals - May consume dying (but not yet dead) specimens
đ Control Options
1. Do Nothing (Recommended for Most)
- Common bristleworms are beneficial
- Population self-regulates based on food supply
- Removing them loses valuable cleanup services
- Focus on reducing excess food if population is huge
2. Reduce Population Through Husbandry
- Feed less - population will decline naturally
- Remove uneaten food promptly
- Improve detritus export (better flow, vacuuming)
- Population follows food availability
3. Trapping
Commercial and DIY traps work well:
- Commercial traps: Various designs available
- DIY bottle trap: Cut bottle with inverted funnel entrance
- Bait with shrimp, fish, or meaty food
- Place in tank at lights out
- Remove in morning
- Effective for reducing large specimens
4. Natural Predators
Several fish and invertebrates eat bristleworms:
- Arrow crabs - Effective bristleworm hunters
- Coral banded shrimp - Will catch and eat them
- Wrasses - Many species eat small worms (Six line, Melanurus)
- Dottybacks - Orchid dottyback hunts bristleworms
- Hawkfish - Opportunistic bristleworm predator
5. Manual Removal
- Use long tweezers or forceps
- Best done at night with red light
- Wear gloves - Bristles can irritate skin
- Grab firmly - they're slippery
- Target large individuals or fireworms specifically
â ī¸ Handling Bristleworm Stings
If you get bristles in your skin:
- Don't rub the area (pushes bristles deeper)
- Use tape or rubber cement to pull bristles out
- Tweezers for visible large bristles
- Rubbing alcohol to clean area
- Hydrocortisone cream for irritation
- Reaction typically subsides in a few hours
đĄī¸ Prevention
- Inspect live rock before adding (remove visible large worms)
- Don't overfeed - smaller food supply means smaller population
- Maintain good husbandry to limit detritus
- Keep arrow crab or wrasse for ongoing control
- Accept that some bristleworms are beneficial and normal
â Common Questions
Did bristleworms kill my fish/coral?
Probably not. Bristleworms are almost always scavengers that arrive AFTER an animal dies. They didn't cause the death; they're cleaning up. The exception is fireworms, which may attack stressed or dying animals.
Why do I suddenly have so many?
Bristleworm populations track food availability. Sudden increases usually mean you're overfeeding, or there's a dead animal decomposing somewhere in the tank.
Should I remove all of them?
No! Common bristleworms are valuable cleanup crew members. Only remove fireworms or manage excessive populations by reducing food input.
đ Summary
Bristleworms have an undeserved bad reputation in the hobby. The vast majority are beneficial scavengers that help maintain water quality by consuming detritus and dead organic matter. Only fireworms - which are larger, flatter, and have prominent feathery bristles - are potential threats to tank inhabitants. Rather than trying to eliminate bristleworms, focus on controlling their population through proper feeding practices. A moderate bristleworm population is a sign of a healthy, well-functioning reef ecosystem.