Sea slugs are some of the most fascinating creatures you can own as pets. With over 3,000 different species, they come in a stunning array of shapes, sizes and colors. If you want a unique pet that will amaze everyone who sees it, a sea slug may be right for you.

Quick answer: Sea slugs can make great pets for the right owner. They require specialized care including a marine aquarium with live coral, proper water parameters, and a diet of live or frozen foods. Handling is not recommended. Costs range from $20-$200 for the slug plus $500+ to setup the tank.

In this comprehensive guide, we’ll cover everything you need to know about keeping sea slugs as pets. You’ll learn about popular species, housing requirements, proper feeding, health and behavior, where to buy them, and much more.

We’ll also bust some common myths and misconceptions about these increasingly popular invertebrates.

Sea Slug Species and Appearance

Popular Species

Sea slugs, also known as nudibranchs, come in a dazzling array of colors and patterns. Some of the most popular sea slug species kept as pets include:

  • Blue dragon (Glaucus atlanticus) – these otherworldly sea slugs are a pale blue color and can grow up to 3 inches long.
  • Spanish dancer (Hexabranchus sanguineus) – named for their graceful swimming motion, these red or orange sea slugs have wing-like cerata on their backs.
  • Leaf sheep (Costasiella kuroshimae) – tiny green sea slugs that resemble floating leaves.
  • Blue angel (Glaucus atlanticus) – electric blue sea slugs with finger-like cerata protruding from their backs.

Color Variations

Sea slugs come in a rainbow of dazzling colors including bright reds, oranges, yellows, greens, blues, purples, and more. Some species can even change color depending on their diet or environment. The vibrant colors warn potential predators that nudibranchs may be toxic or distasteful.

Color patterns and variety differ greatly between species. For example, the chromodoris nudibranch has elegant lines and spots in shades of purple, pink, and blue. Some sea slugs are nearly transparent with striking orange or yellow organs visible through their skin.

The striking colors and patterns make sea slugs extremely attractive pets.

Unique Features

Beyond their colorful appearance, sea slugs have some very unique features. Many species have feathery gills and tentacles called rhinophores on their heads to help them smell. Their backs are covered in finger-like structures called cerata that aid in defense and respiration.

Sea slugs have an oral hood filled with tiny teeth-like structures called radula to help them scrape up food. They move using rhythmic contractions of their muscular foot. While sea slugs lack a protective outer shell, their bright colors and ability to store toxins from their prey help them deter potential predators.

Sea Slug Housing and Habitat Requirements

Tank Size

Most sea slug species require a minimum tank size of 5 gallons, though larger is always better. A 10-20 gallon tank allows you to keep multiple sea slugs together while meeting their space requirements.

Specialty nano tanks around 2-3 gallons can work for a single smaller species like the blue dragon sea slug.

Filtration and Circulation

Good water flow and turnover is crucial for sea slug health. Aim for a filtration system that turns over at least 5-10 times the total tank volume per hour. For example, a 10 gallon tank would need a filter rated for 50-100 gallons per hour. Powerheads and wavemakers help supplement water movement.

Water Parameters

Each species has specific water parameter needs. However, most do best in cool water between 72-78°F with a specific gravity of 1.022-1.025 and pH of 8.1-8.4. Maintaining stable parameters is key. An automatic temperature correction system like a chiller helps regulate temperatures.

Decor and Substrate

Sea slugs need ample places to crawl, hide, and graze for algae in the tank. Include plenty of live rock along with algae-coated décor. The substrate should be a 2-3 inch bed of fine aragonite sand for burrowing. Take care not to trap sea slugs when rearranging décor.

Species Minimum Tank Size Temperature Range
Blue glaucus 5 gallons 68-72°F
Spanish dancer 10 gallons 72-78°F

For more on setting up the perfect sea slug habitat, check out advanced guides on sites like SeaSlugForum and Tonmo.

What Do Sea Slugs Eat?

Sea slugs, also known as sea hares, have a diverse diet depending on the species. Their eating habits typically fall into three categories – herbivorous, carnivorous, or omnivorous. Understanding the dietary needs of each type is critical for proper sea slug pet care.

Herbivorous Species

Herbivorous sea slugs graze primarily on algae and seaweed. Common types of algivores include blue sea hares, sea lemons, and some nudibranchs. When keeping these species as pets, provide a varied buffet from your saltwater tank or harvested seaweed.

Opt for brown, green, and red seaweed to meet nutritional requirements.

Carnivorous Species

Species like Glaucus atlanticus and some aeolid nudibranchs are strictly carnivorous. Their diet consists of sponges, corals, anemones, hydroids, and other small invertebrates. When possible, allow them to actively hunt live prey in the tank.

For picky eaters, target feed shrimp, crabs, or revival food soaked in special sea slug gastronomic juices.

Omnivorous Species

The most common pet sea slugs have an omnivorous diet. This includes colorful nudibranchs and larger sea hares. Offer a mix of meaty items like brine shrimp along with seaweed. Use calcium-fortified preparations as needed to support shell growth.

Target feed reproductive adults 3-4 times per week and juveniles 1-2 times daily.

Feeding Techniques

When feeding sea slugs, use shallow dishes for dried or gel foods. Position live prey on natural surfaces like rocks or wood for hunting. Remove uneaten foods within 12 hours to maintain water quality. Here is a comparison of feeding techniques by species types:

Species Feeding Techniques
Herbivores Graze on clipped seaweed in dish
Carnivores Hunt live brine shrimp introduced into tank
Omnivores Target feed mixed seaweed salad and revival food

With their colorful bodies and unique shapes, sea slugs make for delightful aquarium pets. By tailoring their diets to natural eating habits, sea hare and nudibranch keepers can promote health, growth, and activity.

Sea Slug Behavior and Handling

Solitary Creatures

Sea slugs are generally solitary creatures that prefer to live alone. They are not schooling animals and do not seek out the company of other sea slugs. In fact, most species exhibit territorial behaviors and will defend their personal space from other slugs that wander into their domain.

This does not mean sea slugs cannot coexist in an aquarium, but plenty of room should be provided, and each slug should have its own hideout and grazing area.

Handling Precautions

Most species of sea slugs have fragile bodies that can be easily damaged. Their skin is covered in sensitive cerata that aid in respiration but are easily broken off. It is best to avoid handling sea slugs whenever possible.

If you must pick up a slug, be very gentle and never grab onto the cerata or rhinophores. Cup your hand under the slug or gently scoop under its foot. Never pull on a slug as this can detach the foot. Limit handling to under 5 minutes at a time. Wash hands thoroughly before and after.

Some species secrete toxic or distasteful substances as a defense mechanism. While not necessarily fatal to humans, it is wise to prevent contact with mucus and rinse off any skin or eyes exposed. Wearing gloves while handling or aquascaping is recommended.

Signs of Stress

Watch for these behaviors and signs to know when your sea slug is stressed or unhappy with its environment:

  • Retracted rhinophores
  • Deflated or contracted body
  • Excessive mucus production
  • Clinging to one spot and not moving
  • Loss of cerata or other body parts
  • Lethargy and loss of appetite

If you observe any of these, immediately check water parameters, remove aggressors, and provide plenty of appropriate food. Reduce handling and disturbance until the slug perks up again.

Common Behaviors

Sea slugs move slowly along the bottom, carefully sensing their environment with rhinophores as they graze. They use a muscular foot to creep along and can anchor themselves firmly in place when needed. Many species hunt and scavenge at night.

During the day, they often find a sheltered nook to safely rest.

Reproduction varies greatly by species. Some, like the Spanish Dancer, are hermaphroditic and can mate with any mature partner. Others require a male and female pairing. Most lay loose egg masses rather than internal gestation.

The cerata aid in respiratory exchange but also collect food particles from the water column. Sea slugs that steal chloroplasts and consume algae may supplement their diet through photosynthesis.

Sea Slug Health and Lifespan

Common Health Issues

Sea slugs, also known as nudibranchs, can suffer from various health problems. Common issues include fungal and bacterial infections, parasites, injuries from sharp decorations in the aquarium, starvation, and water quality problems.

Fungal infections typically cause white fuzzy patches on the slug’s skin, while bacterial infections lead to ulcers or abscesses. Parasites like flatworms, nematodes, and copepods can latch onto nudibranchs and feed on them.

Providing a clean tank with smooth decorations, nutritious food, and ideal water parameters can help avoid most health problems.


Before adding new nudibranchs to an established tank, they should be quarantined for a few weeks to monitor their health. The quarantine tank should contain non-aggressive tank mates like hermit crabs that can help indicate the safety of the water quality without harming nudibranchs.

The pH, ammonia, nitrites, nitrates, salinity, and temperature levels of the quarantine tank should be tested frequently and matched to the display tank to prevent shock when the nudibranchs are finally moved to their permanent home.

Typical Lifespan

On average, most sea slug species live for approximately one year. However, their lifespans can vary dramatically between just a few weeks up to five years depending on the species, their living conditions, genetics, reproduction status, and other factors.

For example, the Caribbean sea slug lives six to twelve months while the blue dragon slug only survives one to three months. Providing the optimal water parameters, high quality foods, gentle tank mates, and proper supplements can help maximize a sea slug’s lifespan.

Molting Process

Like other marine invertebrates, nudibranchs must periodically shed their exoskeletons in a process called molting as they grow. Prior to molting, the sea slug stops eating for a few days as a new exoskeleton forms underneath the old one.

It then secretes mucus to separate the old skin and crawls out, leaving its molted skin behind. The process takes around 12 hours. While molting, it’s critical their tank has ample hiding spots and calm conditions to prevent stress.

Most nudibranchs molt frequently when young but the frequency slows as they reach maturity. Shrimp, crabs and other clean up crews help eat shed skins to keep the tank clean.

Where to Buy Sea Slugs

Local Fish Stores

One of the best places to find sea slugs is at a local fish store, especially stores that specialize in invertebrates or saltwater setups. These specialty stores will often have a good selection of colorful species like nudibranchs, sea hares, and various shelled sea slugs available.

When sourcing sea slugs from a local fish store, be sure to inspect the health of the animals closely and ask questions to determine if they have been ethically and responsibly collected. Many local stores also breed sea slug species, which helps conserve wild populations.

Some things to inquire about include what species are captive-bred rather than wild-caught, the origin and collection practices for wild species, the duration sea slugs have been in the store, and tips for selection of healthier, more vibrant specimens.

Choosing a reputable local fish store with knowledgeable staff ensures the highest quality sea slugs and most responsible sourcing practices.

Online Vendors

For those without access to a well-stocked local specialty aquarium store, ordering sea slugs online has become a convenient and popular alternative in recent years. Online sea slug vendors range from large retailers with a wide variety of species and captive-bred options to smaller niche businesses focused on breeding and sustainably collecting uncommon species.

When selecting an online sea slug provider, research their reputation first by checking reviews and customer feedback. Responsible vendors will openly provide information on their breeding programs and collection practices when asked.

Once purchased, most species of sea slugs can be successfully shipped overnight to your home as long as proper insulation and climate control guidelines are followed.

Collecting from the Wild

While beginner sea slug enthusiasts often wish to collect their own specimens from tide pools and reefs, sourcing animals from the wild should be left to experts. Proper identification, optimal collection areas and methods, ethical choices of specimens, and responsible numbers to take require extensive knowledge.

Furthermore, many species have protected conservation status making collection illegal without proper permits. Those set on finding their own sea slugs need to thoroughly research regional regulations and acquisition laws before attempting capture from the wild.

That said, joining a local tidepooling club or conservation group often provides opportunities to discover sea slugs in their natural habitats. These guided experiences allow you to photograph and observe incredible biodiversity without damaging ecosystems or populations.

Ultimately, unless you are a trained professional, purchasing captive-bred and aquacultured sea slug species from reputable retailers remains the best choice for building a unique sea slug aquarium sustainably.

Are Sea Slugs Right for You?

Deciding if an exotic pet like a sea slug is a good fit for your home takes careful consideration. While these small marine creatures have many positive benefits as pets, they also come with some unique care challenges.

Weighing the pros and cons will help determine if their specialized needs and habitats can be met.

Benefits of Sea Slug Pets

Sea slugs, also called nudibranchs, have endearing faces and vibrant colors and patterns that make them delightful to observe. Their small size at 1-3 inches long means they can live in desktop sized tanks.

Over 3,000 diverse species exist in a rainbow of colors like purple, blue, orange, and yellow with names just as fun like the clown nudibranch, dotted sea slug, and blue dragon.

These marine animals are generally easy and low maintenance pets once their ecosystem is properly established. They only live for up to one year, so they are a shorter commitment than dogs or cats. As mollusks, sea slugs lack outer shells and breathe through gills by absorbing dissolved oxygen from the water rather than using lungs.

Filtered saltwater, appropriate lighting and heating, and surfaces for clinging or hiding is all sea slugs require.

Potential Challenges

The saltwater aquatic environment mandatory for a sea slug habitat requires special equipment like filters and protein skimmers. Accessories to test and maintain safe ammonia, alkalinity, salinity, and pH levels is essential for replicating ocean conditions, but this can get technically complex for beginners.

Owners should familiar with the nitrogen cycle and cultivating populations of copepods, amphipods, sponges, and coral for sea slugs to eat. Providing the right water conditions, nutrition, and food sources like marine snow, rotifers, or brine shrimp takes careful research and maintenance.

Some species also require specific water temperatures and air flow environments.

Like any pet, sea slugs need responsible owners who can properly clean tanks and change water as needed. Their lifespan lasting under a year means they pass away more quickly than other pets which can be emotionally difficult for children.

Frequent tank maintenance and equipment costs makes them less than ideal pets for busy households or families on a budget.

Good Fit?

Ultimately saltwater sea slugs require specialty habitats that need significant initial investment and continuous upkeep. Their unique benefits come from observing their bright colors, interesting shapes, and sea-dwelling behaviors.

  • Sea slugs thrive with dedicated owners willing to provide daily care and comfortable replicating a marine ecosystem.
  • People with strict budgets or limited time may find the costs and maintenance too demanding despite their small size.
  • Families with responsible older children willing to help with cleaning and feeding make a better match.

Sea slugs appeal most to aquatic hobbyists passionate about nudibranchs or generating miniature oceans. Casual pet owners often gravitate toward hardier species, but those captivated by their appearance and mystique will delight in sea slugs as pets.

Good Fit For Sea Slug Pets Not a Great Fit
Saltwater aquarium enthusiasts First-time pet owners
Highly motivated for specialized care Those wanting low-maintenance pets
People with extra budget for equipment Busy people lacking time for daily care
Responsible older children helpers Younger children as primary caretakers


Sea slugs can make for rewarding pets, but they do require specialized care and commitment. If you’re fascinated by marine life and ready to invest in a proper saltwater habitat, a sea slug may be a great choice.

With their stunning colors, alien-like appearances and intriguing behaviors, sea slugs are sure to be a conversation starter whenever guests spot them in your home aquarium. Just be sure to do plenty of research and prepare their habitat in advance before bringing one of these unique invertebrates home.

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