Looking to get a pet but don’t have a ton of space? A 20 gallon tank is the perfect size enclosure for certain animals that don’t require massive habitats. Read on as we explore some of the best 20 gallon tank pet options, from fish to reptiles and more.
Fish
When stocking a 20 gallon freshwater aquarium, small, peaceful fish that stay toward the bottom and middle levels of the tank tend to work best. Avoid overstocking by selecting fish with small adult sizes that will be comfortable in a moderately sized tank.
Betta Fish
Known for their vibrant colors and flowing fins, betta fish make excellent additions to 20 gallon tanks when housed singly. Male bettas should not be kept with other male bettas due to aggressive territorial behaviors, but can coexist peacefully with small, non-aggressive tank mates.
Female bettas can be kept in groups of 4-6 fish.
Guppies
Colorful, active guppies bring interest and movement to small planted aquariums. Avoid fin-nipping tank mates and overcrowding. A 20 gallon tank can easily accommodate 8-10 guppies without overstocking concerns.
Platies
Peaceful and hardy, platies adapt well to a variety of water conditions. Their energetic schooling behavior is entertaining to watch. A 20 gallon tank is a good size for a small group of 6-8 platies.
Mollies
Another hardy, live-bearing fish species, the popular molly thrives in slightly brackish water. Avoid mixing them with aggressive fish. About 6-8 mollies is an appropriate number for a 20 gallon tank.
Tetras
Schooling fish like tetras look stunning when kept in large groups. Select tetras that stay under 2 inches like ember tetras, neon tetras, glowlight tetras, etc. A 20 gallon tank can easily house 12-15 small tetras.
Cory Catfish
Peaceful bottom dwellers like cory catfish help clean up excess food and debris. Their active scavenging makes them interesting to observe. A group of 6 cory catfish is a good number for supplementing cleanup crews in 20 gallon tanks.
Aquatic Turtles
When choosing an aquatic turtle for a 20 gallon aquarium tank, some great options to consider are musk turtles, mud turtles, and slider turtles. These small to medium sized turtles can thrive in a tank of this size, as long as proper housing and care guidelines are followed.
Musk Turtle
The common musk turtle (Sternotherus odoratus) is a great small turtle species for a 20 gallon tank. These turtles get to around 3-5 inches in size, so they don’t require a ton of swimming space. Musk turtles have very unique looking shells and faces making them visually appealing in an aquarium. They originate from quiet ponds and rivers in eastern North America.
Some key care guidelines for musks include:
- Water temperature between 75-85°F
- A basking area with heat and UVA/UVB lighting
- An omnivorous diet of insects, plants, fish, and commercial turtle food
- Regular water changes and tank cleaning to maintain water quality
Mud Turtle
Mud turtles like the eastern mud turtle (Kinosternon subrubrum) work very well in a 20 gallon aquarium. They stay on the smaller side, only getting up to around 5 inches in length. Muds love to burrow on the tank bottom and hide under decorations. Some care essentials include:
- Sand or fine gravel substrate for burrowing
- Both dry and aquatic basking areas
- Water temperature between 75-82°F
- An omnivorous diet rich in meaty foods
Slider Turtle
The smallest slider turtle species like redeared sliders (Trachemys scripta elegans) can work in a 20 gallon aquarium when they are young, but will eventually outgrow this size tank. A 20 gallon is suitable for the first year or two of a slider’s life. Juvenile requirements include:
- Water temperature of 78-82°F
- Basking light and platform for full emergence
- A diet rich in vegetables and proteins
- Upgrading to a larger tank as they grow
In the end, musk turtles and mud turtles make the best options for a 20 gallon aquarium when it comes to small turtle pets. With good care and husbandry, these species will thrive.
| Turtle Species | Adult Size | 20 Gallon Suitability |
|---|---|---|
| Musk Turtle | 3-5 inches | Excellent |
| Mud Turtle | Around 5 inches | Excellent |
| Slider Turtle | 10+ inches | Only When Young |
Amphibians
Amphibians can make great pets for a 20 gallon tank. Their small size, minimal care requirements, and interesting behaviors make them well-suited to an aquarium habitat. Some of the best amphibian options for a 20 gallon tank include popular species like fire belly toads, tree frogs, and pacman frogs.
Fire Belly Toads
With their bright orange-red bellies and compact size, fire belly toads (Bombina sp.) are one of the most popular pet amphibians. A group of 3-5 fire bellies can comfortably live in a 20 gallon tank. These small toads only grow to about 1-2 inches long and do well in a humid vivarium with places to hide and a water area for soaking.
Their care is straightforward – feed them small insects a few times per week and maintain their tank environment.
Tree Frogs
Tree frogs like green tree frogs (Hyla cinerea) and gray tree frogs (Hyla versicolor) make excellent display pets. Their bright green colors and large toe pads give them cute appearance. A 20 gallon tall tank is perfect to provide climbing space.
Give tree frogs places to perch both in and out of the water. Feed them live insects like crickets. Their vocalizations can be loud but add to their appeal for some amphibian enthusiasts.
Pacman Frogs
The plump pacman frog (Ceratophrys sp.) is a popular exotic pet frog known for its big mouth and appetite! Despite their large size – they can grow to 5-6 inches – pacman frogs are quite sedentary and actually good candidates for a 20 gallon tank.
Use a basic setup with coco fiber substrate and a large water dish. Feed pacmans a diet of worms and insects. Their comical expressions and feeding behaviors are fun to watch for pet owners.
With a proper setup, amphibians can make for rewarding aquatic pets. Be sure to research the needs of any species before getting an amphibian to have success keeping them. Their sensitive skin and dependence on temperature/humidity means their environments require more careful attention than fish tanks.
Reptiles
Reptiles can make great pets for a 20 gallon aquarium. Some popular choices are small geckos and certain types of snakes. Reptiles are fascinating creatures that come in all shapes and sizes. When properly cared for, they can live for many years.
Let’s explore some of the best reptilian options for a 20 gallon tank.
Crested Geckos
Crested geckos are small lizards from New Caledonia that have become very popular pets. These tropical geckos grow to about 8 inches long and have unique eyelash-like crests above their eyes. Crested geckos are an ideal choice for a 20 gallon tank because they don’t require a lot of space but do well with some vertical climbing room.
Crested geckos are fairly easy to care for. They eat a powdered fruit diet and do not require live insects. Since they are nocturnal, they don’t need UV lighting but do require a warm spot around 85°F. The tank should have plenty of branches, fake vines and plants, and hiding spots to make your gecko feel secure.
Leopard Geckos
If you want a slightly larger lizard, leopard geckos make awesome pets. These terrestrial geckos grow to about 10 inches long. They have yellow and black spotted patterns that resemble a leopard’s coat (thus the name).
Leopard geckos only require a 20 gallon tank when they are juveniles or house alone as adults.
Leopard geckos do well on a diet of live insects like crickets and mealworms. They require a warm spot of 90°F but also need a cool side in their tank. Leopard geckos love to hide so be sure to include a moist hide box and plenty of shelters. With good care, leopard geckos can live for up to 20 years!
Snakes
Certain small species of snakes can also thrive in a 20 gallon aquarium. Good options include rosy boas, Western hognose snakes, and male Kenyan sand boas. These snakes grow from 1-3 feet long, depending on the exact species. They make for calm mannered, easy to care for reptile pets.
Snakes eat whole prey items like mice. Their tanks should have an appropriate sized water bowl, ample bedding substrate, and hides for security. Creating a thermal gradient from 78-85°F with overhead heating allows them to properly thermoregulate.
With their shy and gentle demeanors, small snakes make great display pets.
| Reptile | Adult Size | Diet | Lifespan |
| Crested Gecko | Up to 8 inches | Powdered fruit mix | Up to 15-20 years |
| Leopard Gecko | Up to 10 inches | Live insects | Up to 20 years |
| Rosy Boa | 2-3 feet | Frozen/thawed mice | Over 20 years |
As you can see, small reptiles make awesome, long living pets for a 20 gallon tank. Just be sure to research the specific care requirements for any reptile before bringing them home. With proper husbandry, you’ll have a healthy and thriving scaly friend!
Invertebrates
Hermit Crabs
Hermit crabs are a popular pet for a 20 gallon aquarium. These small crustaceans have soft abdomens so they need to find empty seashells or snail shells to use as mobile homes to protect themselves. There are numerous species, but the most common hermit crabs kept as pets are the Ecuadorian crabs (Coenobita compressus) and the Caribbean hermit crabs (Coenobita clypeatus).
Hermit crabs require specific heating and humidity to thrive with temperatures between 72-80°F being ideal. The tank should have around 75% humidity. They also need hiding spots and ample substrate to burrow in. Good options are play sand mixed with coconut fiber.
You’ll want at least 4 inches of substrate for them to dig tunnels and caves. Add some logs, rocks or reptile hides for them to climb on.
These sociable creatures live together peacefully when properly housed. Aim for at least 3 hermit crabs so they have companions. You can keep up to 10 hermit crabs in a 20 gallon aquarium. Be sure to offer a variety of shells so they can upgrade homes as they grow.
Hermit crabs are scavengers in the wild and will accept a wide variety of foods in captivity. Supplement their diet with calcium powder to keep their exoskeletons strong.
Snails
From bright mystery snails to sleek nerite snails, adding a clean up crew of snails is one of the simplest ways to spice up a 20 gallon aquarium. These entertaining gastropods serve many purposes like consuming pesky algae, aerating the substrate, and adding visual interest.
Mystery and nerite snails are completely peaceful, so they mix well with docile fish, shrimp, and live plants. Ensure any tankmates do not view the antennae-bearing mollusks as food. When setting up their environment, place smooth rocks and driftwood to give them hard surfaces to graze on and rasp with their radulas.
Sand substrates work well but small gravel can trap their fleshy feet.
Fun fact: Well-fed mystery snails may lay egg clutches above the water line. The pink pinhead-sized eggs can hatch in 2-3 weeks given warm, humid conditions. But consider removing the egg mass unless you want an explosion of baby snails!
Shrimp
From vibrant cherry shrimp to whisker-like bamboo shrimp, these delicate crustaceans make engaging scavengers for community aquariums. Shrimp come in a rainbow of colors with different patterns and grade variations.
They stay small, breed readily, and coexist with most fish (except aggressive species who see them as expensive snacks).
While some shrimp like amanos require brackish water, neocaridina and caridina species thrive in standard freshwater setups. Heavily planted aquariums with lots of hiding spots are ideal to help shrimp feel secure.
Consider adding cholla wood, coconut caves, and smooth stones to give algae grazers ample surface area to pick at. Sand substrates are easier on tiny legs versus sharp gravel.
Maintaining pristine water quality is key for healthy molting and breeding. Test kits are essential to monitor GH (general hardness), KH (carbonate hardness), and TDS (total dissolved solids). Shrimp keepers also use supplements like Shrimp King minerals for the perfect water chemistry.
Conclusion
In summary, a 20 gallon tank opens up a surprising number of options for unique and easy-to-care-for pets. From stunning betta fish to cute crested geckos, you’re sure to find a perfect small-space companion.
