Top 10 Invertebrate Species for Cleaner Crews in Refugia in 2027

1. Tisbe Copepods

Tisbe copepods rank first because they are the only refugium invertebrate that cleans and reproduces fast enough to feed a display tank indefinitely. These small benthic copepods graze detritus and microalgae off macroalgae strands, glass, and sump walls without needing dedicated refugium light. A starter bottle runs $20-$35 at typical retailers. Seeded into a predator-free refugium with chaetomorpha, the population sustains itself with no repeat purchases needed.

This is the base culture for keepers of mandarins, scooter blennies, or LPS corals that browse live food. The trade is visibility: Tisbe stay small and hide in substrate, so the population you paid for is rarely seen. Compared with Gammarus amphipods, Tisbe process finer detritus and breed faster, but each individual delivers far less biomass to a hungry wrasse or dragonet.

2. Gammarus Amphipods

Gammarus amphipods take second because they handle the coarse waste copepods cannot, shredding uneaten pellets, decaying macroalgae, and heavy detritus that would otherwise rot in the sump. These shrimp-like crustaceans breed readily in chaetomorpha and migrate through return plumbing into the display. Starter cultures cost $20-$40. Their larger body size makes them the preferred prey of wrasses and other pod-hunting fish in a mixed system.

Stock these if your livestock includes fish too big to bother chasing copepods. The trade-off is competition: amphipods outcompete smaller copepods for food, which is why some reefers run pods-only refugia for finicky mandarinfish. Against the Tisbe copepods above, amphipods add far more detritus-processing capacity but a slower, less continuous supply of live food.

3. Tigriopus Copepods

Tigriopus copepods earn third on nutrition rather than cleanup volume. These bright orange copepods are rich in astaxanthin, the carotenoid that drives red and orange coloration in reef fish, and they swim in the water column where fish can actually hunt them. They are hardier and noticeably larger than Tisbe copepods. A bottle costs $20-$35 and is commonly dosed alongside a benthic culture for variety.

Buy these to add nutritional diversity and visible pods to an established crew. The trade is temperature: Tigriopus is a cold-water species that stresses above 82°F (28°C), so summer spikes can crash the culture. Unlike the Tisbe copepods at rank one, Tigriopus does less surface grazing and is better treated as a supplemental feeding culture than a permanent cleaner.

4. Stomatella Snails

Stomatella snails rank fourth as the best value in the crew because they self-populate for free once established. These small, fast-moving grazing snails reproduce prolifically in a reef system without ever becoming pests, mowing algae and detritus off rock, glass, and refugium walls. They typically arrive as hitchhikers on live rock or cost only a few dollars when purchased deliberately, and colonies keep working with zero ongoing spend.

This is the pick for anyone who wants algae control without buying replacement snails every few months. The trade is unpredictability: you cannot precisely control population size or timing, and hitchhiker arrival is luck. Against the Collonista snails below, Stomatella are larger, active in daylight, and graze more surface area per animal, but reproduce somewhat less explosively.

5. Collonista Snails

Collonista snails place fifth because they breed faster in a protected refugium than almost any other snail while staying too small to ever become a nuisance. These tiny nocturnal grazers work biofilm and algae on refugium walls and macroalgae, then migrate into the display over time to reinforce the main cleanup crew. They often arrive free on live rock; purchased starter populations run $5-$15 per group.

Use them where you want continuous, low-profile algae grazing that does not uproot chaetomorpha. The trade is visibility and speed: they feed at night and each snail clears very little area, so results show over weeks. Compared with the Stomatella snails above, Collonista multiply harder but individually contribute less grazing, making them a numbers play rather than a workhorse.

6. Common Reef Bristle Worms

Common reef bristle worms rank sixth on raw detritus throughput despite their bad reputation. These polychaetes burrow through detritus, uneaten food, and decaying matter in the refugium substrate, recycling nutrients and aerating sand that would otherwise go anaerobic. They arrive free on live rock and breed readily out of sight, and a refugium is the ideal place to let their numbers build unseen.

They suit deep sand beds and heavily fed systems where organics accumulate faster than snails can handle. The trade is appearance and the persistent fear of large predatory species like bobbit worms, which are genuinely rare. Against the Micro brittle stars below, bristle worms reach deeper into substrate but are far less pleasant to encounter during routine maintenance.

7. Micro Brittle Stars

Micro brittle stars rank seventh because they reach detritus nothing else can, working deep into rock crevices and under structure where snails and worms will not go. They split asexually, so a few individuals multiply into a working population inside a refugium. They pose zero risk to fish or corals, unlike larger brittle star species, and frequently hitchhike on live rock or cost $5-$15 as a deliberate starter.

These are for rockwork-heavy refugia where leftover food lodges in gaps. The trade is scale: they are pure scavengers with no algae grazing, so they never substitute for snails. Compared with the Common reef bristle worms above, micro brittle stars are socially acceptable to see and safer to handle, but process less bulk waste in a deep sand bed.

8. Dwarf Cerith Snails

Dwarf cerith snails take eighth as the dedicated sand-bed specialist in the crew. They burrow into and sift the refugium substrate, eating detritus and algae while turning and oxygenating sand, and they will breed inside a reef system over time. Their small shell size lets them work tight corners of a sump chamber that larger cleanup snails cannot enter. A pack typically runs $10-$20.

Stock them if your refugium has an actual sand bed rather than bare bottom or rubble. The trade is narrow scope: on glass and rock they underperform dedicated grazers. Against the Micro brittle stars above, dwarf ceriths handle sand-surface detritus and algae film rather than crevice scavenging, and they cost more than hitchhiker species you get free.

9. Mini Feather Dusters

Mini feather dusters rank ninth because they clean a different medium, the water column instead of surfaces. These filter-feeding tube worms strain suspended detritus and particulates, polishing refugium water while multiplying into colonies across rock and sump walls. They commonly arrive on live rock or cost $5-$15 purchased, and their contribution is passive and continuous, requiring no feeding or intervention once settled in.

They suit systems where fine particulate haze survives mechanical filtration. The trade is that they are sessile and slow to spread, so they add filtration diversity rather than measurable cleanup labor. Compared with the Dwarf cerith snails above, feather dusters never touch substrate or algae and cannot be relied on for nutrient export, so treat them as a supplement, not a crew member.

10. Spaghetti Detritus Worms

Spaghetti detritus worms rank tenth on cost alone: they are free, arriving unbidden on live rock, and they process substrate waste tirelessly once established. In a predator-free refugium these burrowing worms multiply and break down organics, feeding the broader microfauna food web that supports copepod and amphipod populations. Their presence is a recognized indicator of a healthy, established refugium ecosystem rather than a problem to correct.

They are for anyone building a refugium biologically rather than buying it outright. The trade is total lack of control: you cannot order, dose, or count them, and populations swing with feeding levels. Against the Mini feather dusters above, these worms do substantially more real waste processing but offer nothing visually and can alarm owners who spot them during a substrate siphon.

How we ranked these

We ranked species on four weighted criteria: whether each breeds unassisted in a predator-free sump, how much detritus or algae it processes per unit biomass, its survival rate from bottle to established refugium, and its starter cost measured against the size of population it eventually sustains. Copepods and amphipods scored highest because they double as live food for display-tank fish and corals, not just cleanup labor.

We deliberately ignored display-tank aesthetics, adult body size, and anything marketed as a main-tank cleanup-crew package. Hermit crabs, emerald crabs, cleaner shrimp, and larger brittle star species were excluded outright because they hunt pods, turning a refugium meant to produce live food into one that consumes its own output. Brand names were ignored too, since a species breeds identically regardless of which vendor's bottle it arrived in.

Related questions

How long should a new refugium run before it will support a pod population?

Give it three to four weeks before stocking. The macroalgae needs to establish and a biofilm has to build on rubble and walls before copepods have anything to graze. Seeding pods into a sterile, freshly filled sump usually ends in a crash. Add chaeto, run reverse-daylight lighting, let detritus accumulate, then pour in the starter culture.

What size refugium is worth stocking with a cleaner crew?

Anything holding roughly ten gallons or more will sustain a visible pod population, though smaller chambers work but crash faster when temperature or nutrients swing. Surface area matters more than raw volume: a densely packed ball of chaeto in a five-gallon chamber will outproduce a bare ten-gallon sump lit from above with nothing for pods to hide in.

Do amphipods really outcompete copepods in a shared refugium?

They can. Amphipods are larger, shred the same detritus, and will opportunistically eat copepod nauplii. In a refugium with plenty of chaeto and rubble, both populations usually coexist fine. If the goal is feeding a mandarin specifically, running a pods-only 'fuge with no amphipods measurably raises copepod output, which is why that setup has gained traction among reefers.

Should the refugium light run opposite the display lights?

Yes, reverse daylight is standard practice. Running the refugium light while the display is dark keeps macroalgae photosynthesizing around the clock, stabilizing pH overnight instead of letting it sag while the display lights are off. It also means pod activity peaks while display fish sleep, so more of the population survives the trip through the return pump into the tank.

How do pods actually get from the refugium into the display tank?

They travel through the return pump. Copepods and amphipods get drawn out of the sump chamber, pass through the impeller, and arrive in the display alive at surprisingly high rates because they're small enough to avoid being shredded, though larger amphipods fare worse. A refugium plumbed to overflow directly into the return chamber exports more than one behind a baffle wall.

Can a refugium cleaner crew replace mechanical filtration?

No, and it was never meant to. Detritivores relocate and recycle waste inside the system rather than removing nitrate and phosphate from the water column. Actual export happens when you harvest macroalgae and physically discard it. Treat the crew as what keeps detritus from turning anaerobic and feeds the display, not as a substitute for a skimmer or filter sock.

Are bristle worms in the refugium a sign of overfeeding?

A population explosion often is. Bristle worms multiply to match available food, so a sump crawling with them usually means organics are accumulating faster than they're being exported. That's useful information rather than an emergency — cut feeding, siphon the refugium floor, and harvest more chaeto, and the population will settle back to whatever nutrient level the system actually supports.

Do refugium invertebrates survive a tank temperature spike?

Most tolerate the low 80s Fahrenheit briefly without major losses. Tigriopus californicus is the weak link — it's a cold-water species that stresses above roughly 82°F, so a summer spike thins that population first while Tisbe carries on unaffected. If your fish room tends to run warm, weight the crew toward Tisbe and skip Tigriopus rather than fighting the temperature.

FAQ

What is the point of a cleaner crew in a refugium?

It does two jobs at once. The crew processes detritus and grazes algae off macroalgae and chamber walls, while also breeding live food — copepods and amphipods — that drifts into the display to feed corals and pod-hunting fish. Because nothing in the refugium eats them, the population grows faster than the display tank alone could ever crop it.

Which invertebrates breed best in a refugium?

Copepods (both Tisbe and Tigriopus), amphipods, stomatella and collonista snails, and micro brittle stars all reproduce readily in the protected environment and build self-sustaining populations. Micro brittle stars split asexually, so a handful becomes many without needing to pair off. Bristle worms and spaghetti worms multiply out of sight in the substrate wherever detritus collects and feeding is steady.

Do I need to keep buying pods, or do they sustain themselves?

Once established in a predator-free refugium with chaeto, copepods and amphipods reproduce continuously and sustain their own numbers, so a starter culture is normally a one-time purchase. Repeat buying usually means the pods were dumped straight into the display instead of the sump, or the refugium never had enough macroalgae habitat for them to actually breed in.

Are bristle worms safe to have in my refugium?

The common small species are beneficial detritivores and belong there, burrowing through waste and aerating substrate out of sight of the display tank. Only a few large species, notably bobbit worms, cause real problems, and they're genuinely rare in the hobby. A refugium is actually the ideal place to let an ordinary bristle worm population work unbothered.

What macroalgae should I run with the cleaner crew?

Chaetomorpha, universally called chaeto, is the standard choice. It grows fast, exports nitrate and phosphate when harvested, and its tangled structure gives pods, amphipods, and micro-snails enormous surface area to breed on. It also doesn't go sexual and crash the way caulerpa can, which matters a lot in a chamber nobody is watching every single day.

Can these refugium inverts get into and clean my display tank?

Yes, and that's the design working as intended. Pods, amphipods, and many micro-snails migrate from the refugium through the return plumbing into the display, seeding it with live food and extra cleanup labor. Collonista and stomatella in particular spread throughout the whole system over months, grazing rock and glass without ever becoming a nuisance species.

Which species should I add first when stocking a refugium?

Seed copepods and amphipods first, since they need the longest undisturbed runway to establish before anything crops them. Give them a few weeks with the chaeto before the display starts drawing them down. Detritivores — bristle worms, micro brittle stars, spaghetti worms — usually arrive on their own with live rock. Grazing snails like stomatella and collonista come last, once biofilm exists.

How much does a full refugium cleaner crew cost to start?

Roughly $60 to $120 if you buy every paid species. Copepod bottles run $20 to $35 each, amphipod cultures $20 to $40, and starter snails or micro brittle stars $5 to $15 per group. Bristle worms, spaghetti worms, feather dusters, and often stomatella arrive free as live rock hitchhikers, which cuts the real bill substantially for most tanks.

How often should I siphon detritus out of the refugium?

Every four to six weeks is a reasonable interval, focused on the open floor rather than the sand bed or the chaeto itself. The goal is preventing anaerobic pockets in spots the worms can't reach, not sterilizing the chamber. Harvest excess macroalgae on a tighter cycle — every two to four weeks — since that's where real nutrient export happens.

What should never go into a refugium?

Anything that hunts. Mantis shrimp, predatory crabs, hermit crabs, wrasses, and mandarins all belong in the display, not the nursery that feeds it. Adding a hermit crab 'to help clean the fuge' is the most common self-inflicted wound — it eats the very crew you paid for. Keep the refugium strictly predator-free and let the display do the cropping instead.

Sources

• https://www.reef2reef.com/threads/refugium-101.400000/
• https://www.bulkreefsupply.com/content/post/refugium-setup-guide
• https://www.algaebarn.com/blog/copepods/
• https://www.melevsreef.com/refugium
• https://reefs.com/magazine/refugium-basics/
• https://www.advancedaquarist.com/2003/8/aafeature
• https://en.wikipedia.org/wiki/Tigriopus_californicus
• https://en.wikipedia.org/wiki/Chaetomorpha
• https://www.marinedepot.com/blog/refugium-macroalgae

Related on PULSE

• [More invertebrate species for cleaner crews in refugia rankings and buying guides](/knowledge)
• [PULSE Tools and calculators](/tools)
• [Everything on PULSE RevOps](/)