20 Gallon Tank For Hermit Crabs – Your Step-By-Step Guide To A Happy
Are you dreaming of giving your hermit crabs a truly enriching and healthy home? Perhaps you’re upgrading from a smaller setup, or maybe you’re a new hobbyist eager to start on the right foot. Whatever your reason, you’ve landed in the perfect place! Many new crab parents wonder about the ideal tank size and setup, and we agree—getting it right from the start is crucial for these fascinating creatures.
A
20 gallon tank for hermit crabs
is an excellent choice, especially for beginners or those keeping 1-3 medium-sized crabs. It offers a fantastic balance of space, manageability, and affordability. This guide will walk you through everything you need to know, from selecting the right substrate to creating an enriching environment, ensuring your hermit crabs thrive.
By the end of this article, you’ll have all the practical knowledge to confidently set up a crabitat that mimics their natural environment, promoting healthy molting, exploration, and overall well-being. Let’s dive in and build a fantastic home for your shelled friends!
Why a 20 Gallon Tank is an Ideal Starting Point
Choosing the right size enclosure is one of the most critical decisions you’ll make for your hermit crabs. While many sources suggest smaller tanks, experienced keepers know that a larger space is always better for these active, social invertebrates. A 20-gallon tank offers significant advantages.
It provides ample room for deep substrate, which is absolutely essential for successful molting. It also allows for a proper humidity gradient and sufficient space for climbing, hiding, and multiple food and water dishes. Don’t worry—this setup is perfect for beginners!
Space for Exploration and Enrichment
Hermit crabs are naturally curious and love to explore. A 20-gallon long tank (which has a larger footprint than a tall tank) gives them plenty of floor space to forage. This allows you to add various enrichment items like climbing structures and multiple hides.
More space reduces stress and aggression, especially if you house multiple crabs. Think of it as their miniature jungle gym!
Crucial for Successful Molting
Molting is a vital, yet vulnerable, process for hermit crabs. They bury themselves deep into the substrate to shed their exoskeleton and grow. A 20-gallon tank allows for a substrate depth of at least 6 inches, which is the absolute minimum for most medium-sized crabs.
Without adequate depth, your crabs may attempt to molt on the surface, which is incredibly dangerous and often fatal. Providing a safe, deep burrowing area is non-negotiable for their survival.
Easier to Maintain Stable Parameters
Larger tanks are generally more stable when it comes to temperature and humidity fluctuations. A 20-gallon tank provides a larger air volume, making it easier to maintain the consistent high humidity (75-85%) and temperature (75-82°F) that hermit crabs require. Smaller tanks can swing wildly, putting your crabs at risk.
Essential Equipment for Your Hermit Crab Habitat
Setting up a 20-gallon tank for hermit crabs requires more than just the tank itself. You’ll need specific equipment to replicate their tropical environment accurately. Investing in quality gear now will save you headaches later.
The Tank Itself
A standard
20-gallon long aquarium
is highly recommended over a 20-gallon tall. The “long” version provides more floor space, which hermit crabs utilize far more than vertical height. Ensure it has a tight-fitting lid, preferably glass, to maintain humidity.
Mesh lids are fine, but you’ll need to cover most of the mesh with plastic wrap or a solid piece of plastic to prevent humidity loss.
Substrate: The Foundation of Their Home
This is arguably the most critical component. Hermit crabs need deep, moist substrate for molting and burrowing.
- Play Sand: Fine, silica-based play sand (like children’s sandbox sand, not construction sand) is essential. It should be thoroughly rinsed and oven-baked or microwaved to sterilize it before use.
- Coco Fiber (Eco Earth): This compressed coconut husk substrate helps retain moisture and adds to the burrowing consistency. Mix it with play sand at a ratio of 5:1 sand to coco fiber.
- Depth: Aim for at least 6 inches of substrate, or ideally, 3 times the height of your largest crab. This ensures they have enough depth to fully bury and create a molting chamber. The substrate should be sandcastle-consistency—moist enough to hold its shape when a tunnel is dug.
Heating and Humidity Control
Maintaining the correct temperature and humidity is paramount for hermit crabs.
- Under Tank Heater (UTH): A UTH is crucial. It should be placed on the side or back of the tank, above the substrate line, never underneath. This prevents cooking buried crabs and creates a warm ambient temperature. Choose one designed for reptile use, covering about 1/3 to 1/2 of the tank’s back.
- Thermostat: Always connect your UTH to a thermostat with a probe. This prevents overheating and keeps the temperature stable. Set it to 78-80°F.
- Hygrometer/Thermometer: You’ll need at least two digital thermometers/hygrometers—one on the warm side and one on the cool side of the tank—to monitor both temperature and humidity accurately. Aim for 75-82°F and 75-85% humidity.
- Misting Bottle: A simple spray bottle filled with dechlorinated water helps maintain humidity. Mist the tank walls and substrate as needed, usually once or twice a day.
Food and Water Dishes
Hermit crabs need access to both fresh and saltwater at all times.
- Water Bowls: Use non-metallic, heavy, shallow dishes that your crabs can easily enter and exit. Provide two separate bowls: one for dechlorinated fresh water and one for dechlorinated marine salt water. Use a quality marine salt mix (like Instant Ocean or Seachem Salinity), not table salt.
- Food Dish: A shallow, non-metallic dish for food. Hermit crabs are omnivores and need a varied diet.
Setting Up Your 20 Gallon Tank for Hermit Crabs: A Step-by-Step Guide
Now that you have all your supplies, let’s put it all together! This process is straightforward and rewarding. Remember, patience is key.
1.
Clean the Tank:
Thoroughly clean your 20-gallon tank with hot water and a mild, hermit crab-safe soap (like unscented dish soap), then rinse extensively. Let it air dry completely. 2.
Prepare the Substrate:
Mix your sterilized play sand and coco fiber at a 5:1 ratio. Gradually add dechlorinated water until it reaches a “sandcastle” consistency. You should be able to form a ball that holds its shape without dripping. 3.
Add Substrate to the Tank:
Pour the prepared substrate into the tank, ensuring a minimum depth of 6 inches across the entire bottom. You can slope it slightly if you wish, but consistent depth is more important. 4.
Install the UTH and Thermostat:
Attach the under tank heater to the
outside
of the tank, on the back or side, above the substrate line. Plug it into your thermostat and place the thermostat probe
inside
the tank, near the UTH, to monitor the air temperature. 5.
Place Water and Food Dishes:
Bury the dishes slightly into the substrate so the rims are level with the surface. This makes them easier for crabs to access. Fill the freshwater dish with dechlorinated water and the saltwater dish with marine-grade saltwater. 6.
Arrange Decor and Enrichment:
Add climbing branches, fake plants, coconut huts, and other hides. Ensure everything is stable and won’t fall on a burrowing crab. 7.
Introduce Extra Shells:
Place several clean, appropriately sized turbo snail shells (or other preferred species) around the tank. Offer a variety of sizes and openings, as crabs are particular about their shells. Always provide 3-5 shells per crab. 8.
Install Thermometers/Hygrometers:
Place your digital gauges in different areas of the tank to monitor conditions. Allow the tank to stabilize for at least 24 hours before introducing crabs.
Decorating Your Crabitat: Shells, Climbers, and Hiding Spots
Beyond the essentials, furnishing your 20-gallon tank for hermit crabs with engaging decor is vital for their physical and mental well-being. Enrichment prevents boredom and encourages natural behaviors.
Climbing Opportunities
Hermit crabs are natural climbers and explorers. Providing various structures will keep them active and stimulated.
- Cholla Wood: This natural wood is excellent for climbing and gnawing, and it holds moisture well.
- Grapevine Wood: Another great natural option, ensure it’s free of pesticides and thoroughly cleaned.
- Plastic Plants: Securely anchor fake plants to the tank walls or substrate. They provide cover and climbing surfaces.
- Coconut Huts: These offer both climbing opportunities and cozy hiding spots.
Hiding Places
Hermit crabs are nocturnal and appreciate secure places to retreat during the day or when they feel vulnerable.
- Half Coconut Shells: Natural and easily accessible.
- Small Terracotta Pots: Laid on their side, these make great caves.
- PVC Pipes: Cut into short sections, these can be buried slightly for easy access.
Extra Shells: A Fashion Statement and Necessity
Hermit crabs need to change shells as they grow. Always have a variety of appropriately sized shells available.
- Types: Turbo shells, Murex shells, and unpolished land snail shells are popular. Avoid painted shells, as the paint can chip and be toxic.
- Quantity: Provide at least 3-5 clean, empty shells per crab, in various sizes with different opening shapes. Crabs are picky, and having options is crucial.
Maintaining Your Hermit Crab’s Home: Daily Care and Cleaning
A well-set-up 20-gallon tank for hermit crabs requires consistent maintenance to remain healthy. Daily checks and regular cleaning are part of responsible crab keeping.
Daily Checks
- Temperature and Humidity: Verify that your hygrometers and thermometers show stable readings within the ideal ranges (75-82°F and 75-85% humidity). Adjust misting or heating as needed.
- Food and Water: Replenish fresh and saltwater daily. Remove any uneaten fresh food to prevent mold and bacteria growth.
- Crab Activity: Observe your crabs. Are they active? Eating? Have they changed shells? A lack of activity could indicate a problem.
- Substrate Moisture: Check that the substrate is still moist enough to hold its shape. If it’s drying out, mist lightly.
Weekly and Bi-Weekly Tasks
- Clean Dishes: Wash food and water dishes thoroughly with hot water (no soap!) to prevent biofilm and bacterial buildup.
- Wipe Down Walls: Use a clean cloth dampened with dechlorinated water to wipe down the inside of the tank walls, removing any condensation marks or debris.
- Inspect Decor: Check climbing structures and hides for cleanliness and stability. Remove any moldy spots.
Monthly and As-Needed Maintenance
- Deep Clean (Spot Cleaning): Remove any visible waste or uneaten food that might have fallen into the substrate. This is not a full substrate change.
- Shell Inventory: Ensure there are always enough clean, appropriately sized shells. Boil new shells or those that have been sitting in the tank for a while to sterilize them before reintroducing.
- Substrate Replacement (Rarely): A full substrate change should only be done if there’s a serious mold outbreak, pest infestation, or bacterial bloom. Otherwise, spot cleaning is sufficient. Frequent full substrate changes are stressful for crabs, especially if they are molting underground.
Common Challenges and Troubleshooting
Even with the best intentions, you might encounter some issues when keeping hermit crabs. Being prepared to troubleshoot will help you keep your crabitat healthy.
Humidity Too Low or Too High
- Too Low: Crabs need high humidity to breathe. If your humidity is consistently below 75%, cover more of your mesh lid with plastic wrap, mist more frequently, or add a small humidifier outside the tank pointed towards the lid opening.
- Too High: If humidity exceeds 90% for prolonged periods, it can lead to mold. Ensure proper ventilation by uncovering a small portion of the mesh lid, or reduce misting frequency.
Temperature Fluctuations
- Inconsistent Heat: Always use a thermostat with your UTH. Without one, the temperature can spike or drop, stressing your crabs.
- Cold Spots: Ensure your UTH is adequately sized for your 20-gallon tank. If your room is very cold, consider insulating the outside of the tank (excluding the UTH area) with Styrofoam.
Molting Issues
- Surface Molting: This is a sign of inadequate substrate depth, incorrect substrate consistency, or high stress. Ensure your substrate is at least 6 inches deep and “sandcastle” consistency. Reduce disturbances in the tank.
- Failed Molts: Often due to incorrect humidity (crabs dry out) or lack of privacy. Ensure consistent high humidity and provide plenty of hiding spots. Never disturb a molting crab.
Aggression or Shell Fights
- Shell Hunger: The most common cause. Provide a wide variety of clean, appropriately sized shells. Always have more shells than crabs.
- Lack of Space: While a 20-gallon tank is good for 1-3 crabs, if you have more, aggression can increase. Consider upgrading to a larger tank if you have multiple large crabs.
- Dietary Deficiencies: Ensure a varied, nutritious diet, including protein, calcium, and chitin.
Frequently Asked Questions About 20 Gallon Hermit Crab Tanks
Here are some common questions hobbyists have about setting up and maintaining a 20 gallon tank for hermit crabs.
How many hermit crabs can live in a 20-gallon tank?
A good rule of thumb is 1-3 medium-sized hermit crabs in a 20-gallon long tank. If you have larger crabs, you might only comfortably house one or two. Always prioritize space for each individual to thrive and molt without disturbance.
What is the best type of substrate for a 20-gallon hermit crab tank?
The best substrate is a mix of fine play sand and coco fiber (like Eco Earth) at a ratio of 5 parts sand to 1 part coco fiber. It needs to be at least 6 inches deep (or 3x the height of your largest crab) and moist enough to hold its shape for burrowing and molting.
Do hermit crabs need a light in their 20-gallon tank?
Hermit crabs are nocturnal, so they don’t require special lighting beyond ambient room light for a day/night cycle. If you use a light for viewing, ensure it’s on a timer for 10-12 hours a day and doesn’t generate excessive heat. Avoid bright, direct lights at night.
Can I use tap water for my hermit crabs?
Only if it’s properly dechlorinated! Tap water contains chlorine and chloramines that are toxic to hermit crabs. You must use a high-quality dechlorinator designed for aquariums for both their freshwater and saltwater bowls. Additionally, marine-grade salt mix (not table salt) is required for the saltwater dish.
How often should I clean my hermit crab’s tank?
Daily checks for food/water and spot cleaning are essential. Water and food dishes should be cleaned weekly. A full substrate change is rarely needed unless there’s a severe issue like mold or pests. Generally, if your parameters are stable and you’re spot cleaning, the substrate can last for many months, even a year or more.
Conclusion: Building a Thriving Crabitat with Confidence
Setting up a
20 gallon tank for hermit crabs
might seem like a lot of steps, but each component plays a vital role in creating a truly enriching and healthy habitat. By following these guidelines, you’re not just providing a home; you’re mimicking their natural environment, which is the key to their long-term well-being.
Remember, patience and observation are your best tools. Watch your crabs, learn their behaviors, and make adjustments as needed. With a properly set up 20-gallon tank, you’ll enjoy watching these fascinating creatures thrive for years to come. Dive in, have fun, and build a fantastic home for your shelled companions!
