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Best Inverts for a Nano Reef Tank

Nano reef tanks are small saltwater aquariums containing corals or live rock. They usually hold less than 30 gallons of water and are designed for beginner hobbyists or aquarists with limited space. If you have a nano reef tank, you may be wondering which invertebrates/crustaceans are best?

The best inverts for a nano reef tank include bumblebee snails, emerald crabs, fire shrimps, scarlet hermit crabs, nassarius snails, peppermint shrimps, sexy anemone shrimps, and turbo snails. Other small aquatic creatures like tuxedo urchins and sea slugs can also thrive in such an environment.

Now that you know the ‘top 10’ ideal crustaceans for a nano reef tank, let’s ‘dive deeper’ into this topic. Together we’ll learn more about the marine crabs, shrimps, and snails that can live in a 25- or 25-gallon saltwater aquarium with live rock, which ones makes the best tankmates, and how to care for them.

So, if you’re ready to learn more about stocking a nano reef tank with shellfish, then let’s get to it!

What Crabs are Best for a Nano Reef Tank?

When it comes to a nano reef tank, the ideal crab inhabitants are small, peaceful, and won’t harm coral or live rock. The 2 species that best fit this criterion include:

Emerald Crabs

Emerald crabs are scavengers that spend most of their time foraging in and around live rock in search of algae to eat. They originate in the tropical waters of the Caribbean and grow to about 2 inches as adults. Due to their size, only a single emerald crab should be kept in a 20- or 25-gallon reef tank.

Emerald Crabs aren’t just esthetically pleasing but also vital in keeping their aquarium clean. If they’re well-fed, they’ll live amicably with almost any species of marine fish or invertebrate. A nano reef tank with plenty of rockwork crevices to hide in will help them feel stay and remain peaceful.

Scarlet Hermit Crabs

Scarlet hermit crabs are a dwarf species and perfect for a nano reef tank. They’re hardy and stay small, reaching full-grown lengths of a mere inch! Also known as the ‘red reef’ crab, these little crustaceans are found naturally in the warm tropical waters of the western Atlantic.

Scarlet hermit crabs require minimal care and eat mainly detritus or algae. This helps keep ammonia levels down and the aquarium clean. Scarlet hermit crabs can thrive in a nano reef tank with other peaceful fish and crustaceans like emerald crabs and cleaner shrimp.

What Shrimp are Best for a Nano Reef Tank?

Saltwater shrimps are the perfect choice for a nano reef tank. There are at least 3 different species that I know of which won’t pick at corals and can thrive in a smaller aquarium. These include the following:

Fire Shrimps

Fire shrimps (also known as blood red shrimps or scarlet cleaner shrimps) are indigenous to the warm waters of Indo-Pacific and a preferred choice for many saltwater aquarium hobbyists. They only grow to about an inch in length so they’re ideal for a small marine aquarium.

Since fire shrimps will often fight each other as well as smaller shrimps, you should keep just one in a 20- or 25-gallon reef tank. They’re okay with fish, however, and can be kept peaceful types like blue-green chromises, fire gobies, and royal grammas.

Peppermint Shrimps

Peppermint shrimps are highly popular with marine aquarists. Since they’ll only eat dead/dying corals, they pose no threat to healthy live rock in a reef tank. Hardy and easy to maintain, peppermint shrimp stay small (reaching lengths less than 2 inches) which makes them perfect for a nano aquarium.

Because peppermint shrimp don’t take up much space, you can keep 4 in a 20-gallon tank or 5 in a 25-gallon tank. That said, they still need their own individual area to stop them from becoming territorial. They make good tankmates for scarlet hermit crabs and other small, peaceful crustaceans.

Sexy Anemone Shrimps

Sexy anemone shrimps are native to reefs of the Indo-Pacific and make a great addition to a nano reef tank. A one-of-a-kind species, these invertebrates are known for their unique and unusual behavior in captivity. They have distinct coloring and stay tiny, so they adapt well to a nano reef tank environment.

Sexy anemone shrimps are best in kept in groups of 4 or 5. They’re scavengers and spend their days nibbling on excess algae and debris in their aquarium. Peaceful and easy to care for, this species can live amicably with bother emerald crabs and nassarius snails.

trochus saltwater snail

What Snails are Best for a Nano Reef Tank?

Crustaceans like snails are a great addition to a nano reef tank. Best of all, many species are hardy, peaceful, and easy to care for. The 3 that I’d personally recommend are:

Bumblebee Snails

Bumblebee snails are tiny and easy to care for, making them the perfect addition to a nano reef tank. They reach lengths of only half and inch when full-grown and have beautiful black and yellow markings reminiscent of a bumblebee.

Bumblebee snails are great for helping keep their aquarium clean by nibbling at debris and meaty food leftovers lying along the substrate. This keeps dangerous nitrates levels at bay. However, as carnivores they’ll attack and eat other smaller snails so make sure to keep them with larger invertebrates only.

Nassarius Snails

Nassarius snails love to bury themselves in the substrate when not scouring the tank for debris and tiny bits of uneaten food. They’re peaceful, easy to maintain, and won’t pick at corals or live rock in a nano reef tank.

Nassarius snails are non-aggressive and won’t harm other tankmates. Indigenous to the west coast waters of North America, nassarius snails can be kept with just about any saltwater crustacean or marine fish, except for triggers.

Turbo Snails

Turbo snails spend most of their time peacefully grazing on algae. They reach adult lengths of 2 inches and are the ideal ‘clean-up crew’ for a nano reef tank. Native to the Caribbean waters off the Gulf of Mexico, these crustaceans are best kept alone as 2 would likely starve in a 20- or 25-gallon tank.

Turbo snails can be very sensitive to changes in water parameters and must be acclimated slowly to the tank. They need calcium for their shells and can sometimes ‘flip’ over onto their sides or get stuck in between rocks. They make good tankmates for crustaceans of equal size and non-aggressive fish.

What Other Types of Shellfish can Live in a Nano Reef Tank?

Besides crabs, shrimps, and snails, other shellfish like urchins and sea slugs can be kept in a nano reef tank. The 2 types that typically come to mind include:

Tuxedo Urchins

Tuxedo urchins can be kept in a 20- or 25-gallon reef tank, but nothing smaller. They reach full-grown lengths of 2 to 3 inches and are great algae eaters with voracious appetites. This species makes great tankmates for just about any non-aggressive fish or saltwater invertebrate of equal size.

Also known as sphere urchins or globe urchins, this species is found naturally in the tropical waters of the Indo-Pacific and make great tankmates for almost any aquatic creature, even semi-aggressive fish since they’re spines are very blunt and can withstand the occasional nip.

Lettuce Nudibranches

Sea slugs like lettuce nudibranches are sarcoglassans and get their bright green coloring from sucking the chlorophyll out of algae spores. Perfect for a 20- or 25-gallon nano reef tank, they also come in shades of blue, yellow, and brown with a ‘ruffled’ appearance like that of a lettuce leaf.

These inverts are very peaceful. Once settled into their aquarium and with plenty of algae to feed on, they’re quite content on their own. You can keep them with a variety of shrimps, crabs, and snails but be forewarned, they’re not for beginners and are highly sensitive to fluctuating water parameters.

Can Invertebrates and Fish Live Together in a Nano Reef Tank?

Invertebrates and fish can live together peacefully in a nano reef tank. The key is to make sure not to overcrowd the tank and to choose species of like size and temperament. For a 20-gallon reef tank, I’d suggest 8 total inches of fish and for a 25-gallon reef tank, I’d recommend 10 total inches of fish.

All aquatic creatures need their own space, especially in captivity. For fish and invertebrates to live long and happy lives in a confined environment, they must have enough room to swim, forage, and explore their aquatic surroundings. Overcrowding a tank will almost always lead to increased aggression.


To sum things up, the ‘top 10’ inverts for a nano reef tank are bumblebee snails, emerald crabs, fire shrimps, lettuce sea slugs, scarlet hermit crabs, nassarius snails, peppermint shrimps, sexy anemone shrimps, turbo snails, and tuxedo snails.

I hope you’ve found this article helpful regarding how to stock a nano reef tank with shellfish. Thanks for reading and good luck with your aquarium hobby.

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