Everybody wants to have a healthy reef aquarium. So, when it comes to maintaining a thriving tank, there are many things we can do like regular water changes, servicing the filter, testing the aquarium water to make sure that water chemistry remains stable. However, to benefit the reef system, we can also add marine invertebrates to the tank to create a “clean up crew.”
Cleaner shrimp, snails, hermit crabs, etc. will be our vanguard force against algae and detritus. This clean up crew will take care of this for you in absolute majority cases.
I would like to start off by saying that the presence of detritus and the growth of algae in any aquarium is just the natural order of things. In general, algae are harmless other than the fact that it will make your reef tank look really horrible. Therefore, if you do not want to clean it all the time you will need some help.
Once the tank has cycled, and you begin to notice the formation of algae in the aquarium, this is the best time to introduce a clean up crew. Reef safe organisms in a tank are those organisms that are completely harmless or toxic-free to corals present in the tank.
Benefits of the Clean Up Crew in Reef Tank
Although the cleanup crew can be introduced in stages, depending on the needs of your tank and maintenance. It is still a good idea to introduce them right after cycling, as this can help prevent problems from developing in the future.
A clean up crew comes with lots of benefits for your reef tank, some of which include:
- Eating varieties of algae.
- Naturally taking out dirt in narrow spaces that are unreachable by tools or human hand.
- Consuming excess food left by the aquarium life.
- Keeping the water clean and the environment safe for the inhabitants of the reef.
Problems of the Clean Up Crew in Reef Tank
I am sure that you have already seen some articles or videos on the Internet about “Top” or “The List of Best” reef tank cleaners. Well, guess what, in most cases, all these “Top and Best” cannot coexist with each other due to predatory nature.
In addition, there are many species in marine aquarium hobby that can fulfill the role of cleaners. The problem is that their size, or extreme aggressiveness, or food preferences, or everything at once make them a poor choice for the reef tanks.
For example, some species like the Arrow crab, Coral banded shrimp, Sally lightfoot Crab, the reed lobsters, etc. can become too aggressive or dangerous to corals.
With this information, the question that may come to mind would be ‘what is the best reef-safe cleanup crew?’
Luckily, there are invertebrates that fit the profile (more or less). Although not all species of inverts are considered safe, I have put together a list consisting of invert types that are generally considered to be safe enough for the reef tank. They are:
- relatively small,
- generally peaceful,
- mostly herbivorous.
Snails as Clean up Crew
Snails are great cleaners and mostly peaceful creatures. It makes them almost an ideal choice in the water world as a clean up crew. Of course, some of them may not look super cool, but they can make a world of difference and that’s all that matters, right?
Snails move slow but leave nothing behind. They work 24 hours a day. Although you will still need to clean the front glass manually, they will make your rocks spotless clean.
If you are buying them for algae control, the general rule is 1 snail per 5 – 10 gallons (~20-40 liters). Of course, it depends on the conditions of your tank and how many algae you have. Eventually, the snails will deal with this problem and if you have lots of them, it will become problematic to feed them later.
There are many snail species worthy of note, but Astraea snails, Cerith snails, and Trochus snails are the three generally accepted species that help in reef tanks. The Turbo snail is also relevant; however, its large size causing it to tumble rocks in the reef can sometimes be a hindrance.
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Trochus Snails
Personally, I consider this as one of the best snails all around. From the Trochilidae family, this species of snails have a very peaceful temperament. They scout for algae in the water and eat them up, helping to control their rate.
They will clean equally well glass, rocks, and substrate. Trochus snails do not grow too big to become a problem. Another good thing about Trochus snails is that they can right themselves up. So, one thing less to worry about. They can even shake their shells to defend themselves from hermit crabs.
Trochus snails are awesome and, in my opinion, they are the best choice of cleaners for reef tanks.
Feed on: microalgae films (especially diatoms), short turfs of hair algae, detritus.
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Astraea Snails
These snails are from the Astraeinae family. They have a canning passion for clearing brown algae from walls, making them useful in the water. They are notable for their large appetite, so it is best to introduce them in batches and not all at once.
The biggest downside is that Astrea snails cannot upright themselves. Also, their climbing skills are not the best in the snail’s world, therefore, they primarily stay on the substrate and rocks.
Feed on: microalgae films (especially diatoms), short turfs of hair algae, detritus.
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Cerith Snail
Cerith snails will keep your sandbed clean. They prefer to burrow themselves deep into the sands of their environment. However, they will also graze algae off the aquarium walls, decorations, and other hard surfaces, as well. Because of their very cone-like body shape, these snails do not often get stuck to where they cannot right themselves.
Cerith Snails are a fantastic addition to a reef tank cleanup crew. Their small, cone shape shell can get into a lot of crevices that other snails cannot.
The only downside that I can think of is that their eggs came out in strings, appearing like gelatinous white threads attached to various surfaces. Some people do not like how it looks.
Feed on: They like to eat and scavenge for debris. They are able to eat a considerable amount of diatoms, cyanobacteria, film algae, detritus, and hair algae throughout the tanks.
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Turbo Snails
The turbo snail consumes large amounts of diatoms and algae, massively reducing their population in the reef tank. These snails are voracious algae eaters. Most aquarists believe that they are actually the best algae-eater snails in marine tanks.
So, why didn’t I start the reef clean up crew with this species? Unfortunately, there are downsides as well.
- The turbo snails are getting massively huge (up to 7+ cm or 3+ inches). Their size and strength allow them to bulldoze corals and rockwork.
- These snails come from the Gulf of Mexico or the Caribbean and prefer lower temperatures. Therefore, they are not tolerant at high reef tank temperatures (80 F or more).
- While some Turbo snails can flip themselves over, most struggle.
Feed on: microalgae films (especially diatoms), short turfs of hair algae, detritus.
Crabs as Clean up Crew
After snail, crabs (actually, mostly hermit crabs) take the second place as reef cleaner. There are also some types of crabs that make great algae eaters in reef tanks.
The most common species of crabs include hermit crabs, emerald mithrax crabs, and anemone crabs. Depending on your reef livestock, these crabs may not bother anybody. In some cases, they can be completely safe to keep even with other invertebrates. However, there is always ‘But’.
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Hermit Crabs
Their ability to consume algae, detritus, and remains in the aquarium makes them a suitable match for the title of the best reef clean up crew.
The Hermit crab has several common types; the Blue Leg Hermit Crab (Clibanarius tricolor), the Halloween hermit crabs (Ciliopagurus strigatus), and the Red-legged hermit crab (Paguristes cadenati). They all do a great job to keep cyanobacteria and filamentous algae in check underwater.
They are all pretty famous reef cleaners. Their small sizes and little claws let them get in such places where even the small snails cannot get. When looking for food, these hermit crabs will not try to snack on corals. In addition, their size prevents them from knocking over some freestanding corals that are on the bottom.
One or two hermit crabs per 20 – 25 gallons (80 – 100 liters) will be good enough.
For more information, check out my detailed guides about Blue Leg Hermit Crab and Halloween Hermit Crab care.
Warning:
Hermit crabs are small crustaceans that naturally do not have a shell and, therefore, have to “borrow” one from the snails. Ideally, do not keep hermit crabs and snails together. The problem is that Hermit crabs can try to kill them just for their shells. Upside down snails are easy food for hermit crabs.
In addition, once they get big and done with snails, they often go after each other in a battle royale. Eventually, you can end up with one or two hermit crabs out of dozen in the beginning.
Tip: Add more empty shells of different sizes in the tank, it can reduce unwanted ‘interest’ towards other snails in the tank. Unfortunately, in some cases, even having extra shells for them to choose from won’t stop aggression.
Tip #2: Big hermit crabs are also strong enough to knock over corals. So, pick the smallest crabs, they are less aggressive towards snails and work harder.
Feed on: hair algae, cynobacteria, detritus (fish food or fish waste).
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Emerald Mithrax Crabs:
From the family of Majidae, these green and hairy crabs also consume algae and leftovers. However, the reason for their popularity is completely different. Emerald crabs are probably the only thing that will eat the bubble algae.
It is almost impossible to control and eradicate the bubble algae from the reef, but the Emerald Mithrax Crabs do justice to them.
Warning: The problem is that they can become semi-aggressive with time when they get bigger. Emerald crabs require sufficient food as they have the tendency to turn on their fellow invertebrates (snails or hermit crabs) or even small fishes when there is a lack of food.
Feed on: hair algae, bubble algae, turf algae, and detritus.
Tip: If you have Bubble algae in the tank, DO NOT use any nets, scrapers, brushes, buckets, algae magnets, tongs, or any other tools from the contaminated tank in other tanks. In addition, if you need to reach your hands into the contaminated with Bubble algae tank for any reason, be sure to wash and rinse them thoroughly before reaching into other tanks.
Read more in my article “Emerald Crab – Detailed Guide: Care, Diet, and Breeding”.
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Porcelain Anemone Crab
Porcelain Anemone crabs are one of the most peaceful crabs you can find in the aquarium trade. These small crabs live in a symbiotic relationship with Anemones and get along great with just about everybody unless it is Clownfish. These fishes will try to get anemone for themselves and usually win the conflict by evicting the crab.
Porcelain Anemone crabs are good scavengers and absolutely reef safe. They will not harm corals or damage anything in a reef tank.
Another interesting feature of these crabs is that they are are also active filter feeders. They use their fans on their mouthparts to feed on particles (plankton, etc.) suspended in the water column. By doing so, they will clean the water column in the tank.
These crabs can also eat algae, however, it is not their first choice. I have added them to the list because of their unique feeding ability (basically, to clean water) and peaceful temper.
Feed on: detritus in the water and sometimes algae.
Read more in my article “Porcelain Anemone Crab – Detailed Guide: Care, Diet, and Breeding”.
Shrimps as Clean up Crew
Although shrimp cannot compete with snails or hermit crabs for the title of the best clean up crew. They will still benefit reef tanks in their own way.
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Peppermint Shrimp
Peppermint shrimp (Lysmata wurdemanni) are widely used in marine aquariums as a clean up crew, due to their interest in consuming pest anemones, which are usually difficult to remove from a reef system. They will eat every last speck of the pest anemones, so that they will not grow back.
These shrimp are social and enjoy the company of their species members. Peppermint shrimp will not bother other invertebrates in your reef tank. They are peaceful and easy to care for.
The only problem is that they are also shy and prefer to hide behind rocks most of the time.
Feed on: Aiptasia, detritus.
Note: Unfortunately, not only aquarists but even aquatic shops often confuse different species that look like Lysmata wurdemanni (for example, Camel shrimp (Rhynchocinetes durbanensis) or Lysmata boggessi (the Atlantic Peppermint shrimp). These shrimp can be dangerous for the reef tank.
Read more in my article “Peppermint Shrimp – Detailed Guide: Care, Diet, and Breeding”.
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Skunk Cleaner Shrimp
These shrimp (Lysmata amboinensis species) are very popular in aquarium hobby because besides being great scavengers, they also remove parasites from fishes. Yes, they play a vital role in preventative care against parasites of ornamental fish. The “client” fish can even queue up as they wait their turn to be cleaned.
Note: Some aquarists do not have any luck with Cleaner shrimp doing their ‘curing job in tanks. It is hard to say why but it can happen.
Skunk cleaner shrimp are not aggressive and entirely reef-safe. This is a very active shrimp species, they are not afraid to spend most of the time in the open.
Feed on: detritus, remove dead skin, and parasites from fishes.
Read more in my article “Lysmata amboinensis – Detailed Guide: Care, Diet, and Breeding”.
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Blood shrimp
The Lysmata debelius species also has other names such as Red Fire Shrimp, Fire Shrimp, or Scarlet cleaner shrimp. These shrimp are great scavengers and sometimes can also clean fish.
Unfortunately, there are some mixed reports about them. Some aquarists say that they saw them going after snails, hermit crabs, and even other types of shrimp. While others did not have any problems with them. Basically, it is a hit or miss situation.
In addition, unlike Peppermint shrimp, they do not get along with each other, unless it is a mated pair. So, if you think that you can keep several Blood shrimp in the same tank, you are wrong. They really do not like others of their species and will fight to the death.
Feed on: detritus, remove dead skin, and parasites from fishes.
Read more in my article “Lysmata Debelius Shrimp – Detailed Guide: Care, Diet, and Breeding”.
Urchins as Clean up Crew
There are lots of different types of sea urchins in the aquarium hobby. However, most of them will not suit reef tanks simply because of their size and sharp spines that can pierce coral tissue. Big Urchins will also bulldoze most rock formations. We do not need any of that.
Although small species (like Echinometra lucunter, Mespila globulus (Blue tuxedo), etc.) should not become a problem. I would still recommend to firmly secure rocks and corals.
Sea Urchins might not be that effective as snails or hermit crabs, they still can help you to get rid of fine and filamentous algae. In addition, you do not have to worry about anything else disappearing.
Warning: Sea Urchins often go to work on Corallane algae as well. So, keep it in mind, if you would not like that. In addition, be very careful with their spines, some species can be extremely dangerous to the aquarist.
Personally, I’d leave it for a time being and be ready to remove if it becomes troublesome.
Feed on: algae.
For more information read the article “Tuxedo Urchin Urchin – Detailed Guide: Care, Diet, and Breeding“.
Are Sea Cucumbers and Sea Stars Reef Safe?
What about Sea Cucumbers and Sea Stars you might think? Sure, there are some articles and Youtube videos where people say that they keep them in their reef tanks for years without any problems.
Personally, I would not use any of these creatures and I will explain to you why.
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Sea Cucumbers
Sometimes people include Sea Cucumbers in their reef-safe clean up crew. Well, let me strongly disagree.
On the one hand, it is true that the Echinoderms family, the sea cucumbers have a very useful job of keeping reefs clean. By breaking down detritus for the bacteria to feed on, they maintain the nutrient recycling process.
They are natural scavengers and survive by feeding on debris. They pose at corners of the reef and only come out to scavenge for their meals. They are not difficult to take care of.
On the other hand, when stressed or injured they can eviscerate themselves and wipe out an entire tank of fish. Sea Cucumbers release saponins (these are very powerful and dangerous toxins, even for humans).
So, no, I do not think that they are reef-safe. The potential risk is way too high.
Feed on: detritus.
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Starfish or Sea Stars
They are shaped like stars as their names imply. They have a large variety of species covering seas and water bodies in all locations. The majority of their species are covered in bright colors like orange, blue or red, making them attractive.
The main problem with them is that we often do not know what kind of species they are!
Some Sea Stars are predatory and can eat slow-moving invertebrates like snails, hermit crabs, or even fish. The others are too big to damage or even munch on corals (for example, the Chocolate Chip Starfish).
Of course, they are effective scavengers (eating both waste and uneaten fish food). But because a lot of people have a mixed experience when it comes to starfish, I would not use them in a reef tank as cleaners. They may be fine for a while but there is always a huge risk.
Note: If you have too many starfish in the tank, use Harlequin shrimp. These shrimp feed exclusively on starfish.
Should You Feed Your Cleanup Crew?
Clean up crews are often viewed as simple scavengers, with the idea that they can survive on naturally growing matter and the leftovers from feeding community fishes.
Actually, this is problematic for two reasons:
- If there is leftover food, it means that you are overfeeding the tank in the first place. Therefore, adding something that will supposedly clean it is not the solution. The solution is to feed less.
- Clean up crew should not be treated just as reef tank janitors. If there is not enough food for them they can starve, die, or even become aggressive.
However, as long as there are sufficient algae in your tank there will be plenty of food for them to eat. Therefore, if you start giving them something else they can start eating what is easy and tasty.
It seems like the question does not have an easy solution except keeping things balanced. Depending on your tank set up, once they eat all (most) algae, they may need to be fed supplementally for long-term maintenance.
Dealing With Unsafe Inverts
As listed above, not every invertebrate is reef safe. Some examples of unsafe inverts have been listed in the article. Another notable type of unsafe crew is the Sea apple.
An adult sea apple can be up to 8 inches long. They feed mainly on Plankton. The unsafe trait about the sea apple is the ability for it to emit toxins when offended. Although this is only a defense mechanism, the toxins can be very harmful to other creatures in the water, making the sea apples generally unsafe for the reef.
Outside the vertebra world, the non-planktivorous butterflyfish, the triggerfish, and angelfish are examples of the unsafe crew. They are aggressive and harmful to corals. In fact, the main food of the butterflyfish is the coral polyps, so you are sure that the moment you introduce this species into your tank, the number of your corals slowly starts to reduce until they are finally gone. The triggerfish also feeds on smaller fishes in the reef, making it unsafe.
The best advice I can give – if you are not sure, – avoid it or you can use any of the suggestions above to be on the safe side. Well, at least you will know what to expect.
In Conclusion
Having clean up crew in a reef tank is a great advantage. However, all of them have their limitations. It is crucial to understand that even the best cleaners cannot compensate, for example, the presence of dissolved pollutants, which act as fertilizer for algae.
Do not put all your hope on the clean up crew. You need to limit dissolved nutrients in the system, do vigorous protein skimming and water changes as well to keep troublesome algae in check.
Your best bet is to look at reef cleaners as part of the equation, not as a sole solution to it.
Related articles:
List of Saltwater Aquarium Snails: Pros and Cons
Top 10 Corals for Beginners