All About Aquatic Turtle Tanks!

All About Aquatic Turtle Tanks!Aquatic turtle tanks are very gratifying. Not only are pet turtles the most charismatic and outgoing of the reptiles, they’re also some of the longest-lived. Most common pet species can live for well over 30 years in captivity if well cared for. This makes them very rewarding, long-term additions to the home.

Considering the length of time you will have with your turtle, it only makes sense to prepare suitable accommodations for it.

Never forget that captive aquatic turtles will never enjoy the freedom of their wild counterparts, so provide, at minimum, a basic setup to keep your turtle healthy and its enclosure clean. When looking for a tank, it’s a good idea to keep the following points in mind.

Turtle Tubs/Stock Tanks vs. Aquariums

A 20 gallon tank makes a fine temporary home for very young or hatchling turtles, but they grow quickly so it’s best to buy a tank big enough to house an adult. Most sources urge you to size your tank by providing at least 10 gallons of capacity for each inch of carapace (shell) length. For most common basking turtles that can get to around 7 inches or more, this would require a tank of more than 50 gallons. If you want two or more turtles in your tank, then take the largest specimen, use the 1 inch = 10 gallons rule, and then add an additional 10-20 gallons for each additional turtle depending on size. While it is certainly possible to keep turtles in smaller quarters, especially if the water is very well-filtered and the tank is diligently maintained, you should try to come as close to the 1 inch = 10 gallons guideline as possible.

Aquariums are nice for side-viewing but larger ones are very expensive and (if glass) very heavy, fragile and hard to move around. Moreover, most tend to be too tall, which results in relatively little floor space in proportion to their capacity. It is floor area that is most useful for aquatic turtles, so very deep aquariums typically have a lot of unusable space. That is why we’ve identified some inexpensive and spacious Low-Cost Tanks consisting of shallower plastic tubs and plastic stock ponds. For example, the following 50-gallon Rubbermaid Black Stock Tank has more floor area than a standard 55-gallon, and comes at less than half of the price.

Plastic tubs make inexpensive turtle tanks.

Likewise, for bigger turtles and those with more room to spare, there are much larger stock ponds available. Whether you are looking for a 100 gallon tank, 300 gallon tank or something even larger, it’s generally much more cost-effective to use these plastic tanks compared to glass aquaria.

The Importance of Adequate Filtration

In addition to getting a correctly-sized tank with ample floor space, the next most important consideration is filtration. This is where most people make innocent mistakes that result in sick or unhappy turtles and nasty-smelling tank water. We’ve put together a detailed discussion on the topic already: All About Filters.

Clean water is a requirement for all turtle tanks.However, to give you the short version, a high-quality filter is needed to handle the large volumes of waste produced by aquatic turtles. In addition to the solid waste turtles produce, they also excrete copious amounts of ammonia, which is essentially their form of urine. Ammonia is also created as uneaten food and other organic matter decays in your tank. Ammonia is toxic to aquatic vertebrates, especially fish, which can be killed at trace levels. It can make your turtle’s mucous membranes irritated at moderate levels and, at higher concentrations, could pose a serious health hazard. Keep in mind that turtles must drink their own tank water  – forcing a turtle to live in water filled with waste is therefore forcing it to not only live with, but also ingest its own waste products. Moreover, the presence of ammonia will surely offend you too, since it makes turtle water stink so bad your eyes will water!

Steer clear of dinky internal filters that manufacturers love to lure newbie turtle keepers with. Yes, they are often inexpensive but they are all but ineffective for anything but hatchling turtles. To make matters worse, there is usually a hidden cost. They are often sold with filter “cartridges,” usually filled with activated carbon, that will require constant replacement every couple months as they become exhausted. You don’t need any of that. Activated carbon is marginally useful for some things, but does nothing to remove ammonia, which is the only real thing your filter must do well. A good filter does not need activated carbon at all.

Any knowledgeable turtle keeper will tell you that the best filters for aquatic turtles are canister filters. Why? Because they are made to hold lots of filter media – media that creates a matrix for large colonies of denitrifying bacteria that will take hold, usually 4-6 weeks after a new tank is set up with inhabitants. It’s these bacteria, not any cartridge you can buy, that breaks down ammonia. To this day, nothing removes ammonia as effectively or reliably as these “beneficial” bacteria. However, the less media your filter holds and the weaker the flow rate, the less oxygenated 3D surface is available for bacteria to grown on. That’s why most internal filters or hang-on-back filters are just too wimpy for the high rates of ammonia removal that turtles require.

While canister filters are bit more expensive than your average type, the odor-free and clean water they help produce more than make up for their slightly higher up-front cost. Moreover, there are some excellent deals available on some powerful units. Take a look at some of our picks for best turtle filters, you might be surprised to see how affordable powerful filtration can be.

Basking Platforms

No matter which types of aquatic turtle you are interested in, they will all require at least some land area in their enclosure that they can easily get to.

A basking area should be provided in all turtle tanks.For most common basking type turtles, such as sliders, map and painted turtles, you should shoot for a land area that is at least 1/4 the area of the tank. Again, this is not set in stone, and for very large tanks a proportionally smaller land area may be fine. The most important things to remember is that the “island” should be big enough for them to move around on, and provide some options (e.g., cooler/warmer spots) when basking under heat lamps.

Basking areas can be made cheaply with bricks, rocks, or bogwood piled up at one end of the tank to create a natural slope for easy access to/from the water area. They can also be made using Styrofoam (for smaller turtles) or, with a little more work, plexiglass or other materials sufficient to support larger animals.  Fortunately, if you are not into the DIY thing, there are some very good pre-made options out there, which we discuss in detain in our article devoted to The Best Turtle Basking Platforms.

Heat Lamps & UV-B Lighting

Most aquatic turtles regulate their body temperature through basking. Indeed, all of the common sun-bathing species, like sliders and painted turtles, will spend much of their day sitting under a light source to maintain proper temperatures for foraging and digestion. And even highly aquatic turtles like musk turtles and snapping turtles will emerge from time to time to warm up on land areas, so a heat lamp should be present in any tank. Temperatures directly under the heat lamp should approach 90-100F, and then cool off as you move away. That is why it’s important to have a land area large enough to create a gradient of heat; it allows you turtle to pick the desired body temperature by moving closer or farther from the heat source as necessary. There are light bulbs that produce heat, or ceramic heaters that can produce heat without any light at all.

In addition to creating a hot spot in the land portion of the tank, it’s always encouraged to provide UV-B light as well. UV-B light allows turtles (and people) to synthesize vitamin D3, which is vital for proper calcium assimilation and critical for healthy bone and shell development. This is especially important for hatchling turtles that are growing rapidly; any calcium or D3 deficiency can easily lead to permanent growth abnormalities. There are relatively inexpensive UV-B light emitting compact florescent bulbs that are very effective. These bulbs can be trained on the same spot your heat lamp is directed on, so your turtle gets vitamin D3 as it basks, which is what happens in nature.

Since both heat and UV-B lighting are best provided together, it may make sense to get a combination fixture that provides both. For example, Zoo Med makes a good combination fixture that allows you to provides heat and UV-B light simultaneously.

In case you are wondering, yes it is possible to skip the UV-B lamp and provide vitamin D3 via dietary sources. However, even if using a vitamin D3-fortified turtle food with supplementation, your turtle still may not get sufficient amounts of D3. Supplementation is only as good as how well it sticks to food, and some turtles may not eat enough fortified foods to get a proper dose of D3. So, by provide UV-B through lighting, you can more likely close any “dietary gap” and help ensure proper bone and shell development. If at all possible, UV-B lighting is strongly encouraged, particularly for hatchling and immature turtles.

Rethink Using Substrates

While some small, highly-aquatic species, like musk turtles, can benefit from a natural-looking tank floor with lots of wood and 3D terrain, for larger and typical basking turtles, you may want to skip it.

A bare-bottom tank is much easier to clean; substrates are usually for people, not turtles.As stated earlier, aquatic turtles are veritable waste-generators. If they are not producing the waste directly, they are doing so indirectly by being very messy eaters. Most turtles will shred their food as they eat it. Both the waste they produce and these pieces of uneaten food are easily lost amidst substrates, decorations and other items in the tank. Hard to reach or even see, this waste and organic matter then decays and put’s even more strain on your filter. The result can be very smelly tank water and a highly irritated or sick turtle.

In most cases, we recommend scrapping the tank substrate altogether, and if using rocks or other items to create a basking area, try to elevate them enough so you can still fit a small siphon tub around them to suck up debris. Your turtle will not miss the substrate, and will be much happier in a bare-bottom that remains clean, vs. a natural-looking tank that maintains high levels of ammonia.

Heating – Is it Necessary?

Most commonly-available aquatic turtles are from north America where they inhabit bodies of water that can be quite deep and therefore hold cool water year-round. Consequently, in the average home, your turtle should not need heated water. It is sufficient that they be able to bask when they want to. If, however, you are keeping the tank in a room that is very cool for some reason, either a basement area or a room that gets cold in winter, then a submersible heater fitted with a heater guard to prevent burns is a good idea to prevent water temperatures from dropping much below 70F. This is especially important for species that ordinarily hibernate in winter; a sharp seasonal drop in water temperature could signal to them that it’s time to stop eating and prepare for a long rest. Any turtle that is not eating and not actually hibernating is in jeopardy, since this can result in rapid and dangerous weight loss. Due to the slim margin for error, hibernating turtles should be considered only as a last resort for most inexperienced turtle keepers.


Maintenance is a key aspect to aquatic turtle care.Now that you’ve got the right tank, installed a good filter, and are providing a proper heated basking area, you must plan tank maintenance. Just as with fish tanks, you will need to periodically change the tank water to keep the water fresh and the tank clean. No matter how good the filter, water changes are essential for keeping levels of ammonia low enough for nitrifying bacteria to be able to keep up with your turtle’s waste production. Remember, your turtle’s tank is also its toilet bowl!

The good news is that, with a solid canister filter, your work is greatly minimized. I would suggest you strive to change at least 50% of your turtle’s water once a week. Yes, you may be able to get away with doing it less often, but I wouldn’t recommend it. In fact, doing this twice a week is even better, and may be necessary if your tank is undersized or you are housing lots of turtles. Remember to try and vacuum up any debris and solid waste you can find; this is best done with a good aquarium siphon, like the Python series that can both remove and replace tank water.

Rinsing out your tank every once an a while is also a good idea. I recommend doing this outside with a garden hose. Please always remember – never use hot water or soap when routinely maintaining these tanks, or their filters for that matter. Sterility in a your tank is not possible anyway, and you are only going to kill the beneficial bacteria – the ones that break down turtle waste! These bacteria grow on all surfaces of the water-portion of the tank, not just the filter. As such, rinse everything with cool water to disturb them as little as possible, and do not soak anything in tap water (as this has chlorine, which can also kill the good bacteria). A brief rinsing in chlorinated tap water, however, is OK, as established colonies of nitrifying bacteria can resist a brief exposure to chlorine. Likewise, when cleaning out your filter, a quick rinsing of the media is all that’s necessary. Anything more and you may effectively render the filter useless by resetting to it’s sterile, inactive state.

The Fun Part – Tank Setup

Once you have figured out which among the various types of aquatic turtles you want as a bet, you need to plan out your tank setup. We’ve provided a guide for a Basic Turtle Tank Setup, but feel free to go far beyond this. Your turtle will enjoy as much freedom as it can get, and I think you will find them a much more rewarding and healthy pet if you do.

Ponds vs. Tanks

Turtle tanks are great, but ponds are much better!If you have the luxury of keeping your turtles outdoors in a pond-type setup, this is always advisable. You must of course make sure that your turtle is protected from other pets and predators, and more importantly that it is a species that is suitable for maintaining outdoors. In other words, don’t try keeping a southern species outdoors year-round in northern Michigan! Yet, even if housed there during just the summer months, a pond provides a much more realistic setting that both you and your turtle will enjoy. Moreover, if the pond is located in direct and unfiltered sunlight (e.g., no glass or plastic coverings), then you will not need a heat lamp or UV-B supplementation, since sun is the best source of both!

There are many ways to construct a turtle pond, but probably the easiest and best way is to use a very large stock tank, and merely dig it into the ground for a more natural look. For example, a 625 gallon stock tank would make an excellent backyard turtle pond for several adult red-eared sliders.

As far as maintaining water quality in these ponds, I recommend adding fast-growing, floating pond plants, such as water hyacinth (which take up ammonia and nitrates), in conjunction with a good pond filter that also provides aeration.

Key Supplies & Accessories

A ready-made basking platform is a good purchase for most people.Turtles are big business. Unfortunately, this means that there are a lot of products aimed at aquatic turtles, with most being ineffective, overpriced, or simply unnecessary. In terms of what matters, we’ve devoted a guide to Selecting Turtle Food, and have featured all of favorite Filters, Turtle Basking Platforms, and Other Turtle Supplies that you are likely to need. In fact, if you don’t see the item referenced or discussed here, you probably don’t need it! The great thing about turtles is that, once their basic needs are met, they are very tough and undemanding pets. Focus on things like quality and varied food, good filtration, proper tank size/setup, and performing routine maintenance; your turtle will take care of the rest!

Popular Turtle Species

There are many types of aquatic turtles that do well in tanks. However, small freshwater turtles, like the musk turtle, make some of the best captives because they can be housed in smaller tanks and put less of a strain on water quality.

There are many aquatic turtles that make great pets, but stick with smaller species if space is an issue.Nevertheless, the most popular turtles as pets tend to be larger, showier basking species, such as the red-eared slider and painted turtle. These species with their bold colors and outgoing personalities have enamored children and adults for decades, and are likely to remain popular for the foreseeable future. Fortunately, as long as they’re given sufficiently roomy tanks, they are undemanding captives.

Be careful if considering larger, predatory species like snapping turtles. This is not to say that they are not fascinating or can’t make good pets, but their large adult sizes and extremely messy eating habits make them suitable for only very large enclosures and experienced keepers. If you’ve found a baby snapper and would like to keep it for a while, there’s no harm in that as long as good temporary accommodations are provided. But it’s best to decide early whether or not you can house it adequately as an adult, or whether it would be best to set it free where it can live comfortably as it should.

And if you are going to set a baby turtle free, make sure to do it early in the season, especially in northern latitudes – releasing a turtle in the autumn may not give it enough time to prepare for hibernation, and may cause the turtle to die overwinter due to your procrastination.

More info:

Nature/turtle photo credits (in order of appearance):

Zippo Zimmerman under CC BY-SA 2.0

Johndal under CC BY 2.0

delta407 under CC BY-SA 2.0

Jorge under CC BY-SA 2.0

JoshuaDavisPhotography under CC BY-SA 2.0

Shawn Thomas under CC BY-ND 2.0

Jen Wakefield-Dillier under CC BY 2.0