Water Quality for Amphibians and Reptiles

June 6, 2024 Cermedia

Although amphibians and aquatic reptiles might not spend all their time underwater, as fish do, they still require good water quality to stay happy and healthy. In this blog, we will break down why water quality is important, and what you can do to maintain an optimal environment for aquatic reptiles and amphibians.

Importance of water quality for aquatic reptiles and amphibians

Aquatic reptiles and amphibians are diverse groups of animals whose care needs vary greatly from one species to the next. But one thing that they all have in common is that they need clean water. Whether they spend all, most, or even just some of their time in water, aquatic reptiles and amphibians are highly sensitive to heavy metals, chlorine, and chloramines commonly found in tap water. For this reason, it’s important to test and condition any water that you use in your tank, whether it comes from the tap, or other sources.


Just like fish, aquatic reptiles and amphibians are also sensitive to natural wastes that will break down, via the nitrogen cycle, into ammonia, nitrites, and nitrates. These compounds come from the animal’s waste and from dead plant matter and excess food.

Reptile health and water quality

Aquatic reptiles include turtles, as well as some species of snakes and lizards. Examples of aquatic reptiles commonly kept as pets include the red-eared slider turtle, Chinese water dragon, spotted turtles, and water anoles. Even though they don’t have gills like fish do, aquatic reptiles still spend a lot of their time swimming, and they also drink the water. If their water is dirty or contaminated, aquatic reptiles can suffer from bacterial and fungal infections, eye and skin irritation, and diseases of the shell, respiratory and digestive systems.

In comparison to other aquatic animals, turtles produce large amounts of waste. For this reason, turtle tanks often require more frequent water changes than other aquatic animals, both to keep odors down and to maintain the health of the turtle. To minimize maintenance needs, the tank should be properly sized, at a minimum of 10 gallons per inch of turtle shell. The larger the tank, the slower it will become polluted, and the less water changes will be needed.

Amphibian health and water quality

Amphibians are a diverse group that includes frogs, toads, newts, and salamanders. Habitat needs will vary widely by species, so it’s always best to consult a reputable care guide to understand the specific needs of any animal you intend to keep. Most amphibians are semi-aquatic and will spend at least some time above water. Fire belly newts, for example, need both an aquatic habitat for swimming and a warm terrestrial habitat for basking.

Fully aquatic amphibians, on the other hand, do not need any terrestrial habitat. An example of this is the axolotl, which is a type of salamander that has gills and lives exclusively underwater. African dwarf frogs similarly have no need for land, but they have lungs and must surface often to breathe, so their tank shouldn’t be overly deep. It’s also worth noting that amphibians’ habitat needs may change at different life stages. This is because many amphibians begin life with gills but develop lungs as they mature into adults; such is the case for tadpoles as they mature into frogs.

Given that they spend so much of their life in water, many amphibians have highly permeable skin that absorbs water, oxygen and minerals from their environment. Those amphibians with gills absorb oxygen from water exactly as fish do. Because of these characteristics, amphibians tend to be more sensitive to water quality issues compared to reptiles. Like fish, amphibians are extremely vulnerable to nitrogen compounds in their water and can be sickened by even extremely low levels of ammonia and nitrite. Amphibians are also very sensitive to heavy metals, pH, oxygen content, and temperature. If proper water quality parameters are not maintained, amphibians can suffer from lethargy, loss of appetite, equilibrium problems, color changes, chemical burns, respiratory problems, and death.

How to maintain water quality for aquatic reptiles and amphibians

It’s clear why water quality is important, but let’s talk about how to maintain good water quality in aquatic reptile and amphibian tanks. Maintaining your aquarium or paludarium is really quite simple—you just need a little knowledge and a consistent routine.

Cycling a new tank

First things first: if you’re planning on starting a new amphibian or aquatic reptile tank, you’ll need to spend some time cycling your tank. In aquariums and paludariums, tank cycling is a critical preliminary step to establish beneficial bacteria that will control ammonia and nitrite levels in the water. These bacteria drive the nitrogen cycle, an important process where ammonia is broken down into nitrite, nitrates, and in some cases, into innocuous nitrogen gas.

There are several ways to cycle your tank which a can take anywhere from 2-6 weeks to complete.

  • You can add an animal to the tank, and closely monitor the water making sure ammonia levels do not climb too high, making water changes as necessary. The bacteria will come naturally.  During this time, beneficial bacteria will feed on the ammonia and naturally colonize the surfaces in your tank and biofilter media.
  • You could add bottled beneficial bacteria to help the system get a head start.
  • You could also add chemical ammonia into an uninhabited tank, simulating the ammonia produced in a natural environment. In this case, make sure the system is cycled before adding animals.


Filtration is an important part of maintaining a clean environment for any plants and animals living in your tank. There are two main types of filtration that you should use for routine maintenance of your aquatic reptile or amphibian enclosure:

  • Mechanical filtration physically screens out solid particles like feces, dead plant material, and excess food by passing water through a filter pad, sponge, floss, or other media. This type of filtration is particularly important in paludariums, since substrate, soil, and plant material from the terrestrial area can easily get tracked into the aquatic area. In this way, mechanical filtration helps to prevent clogs in biofilter media and makes it easier to keep the water clear of solid wastes.
  • Biological filtration uses beneficial bacteria to break down naturally occurring wastes like ammonia, nitrite, and in some cases, nitrate. Biological filtration media is essentially a substrate that houses beneficial bacteria while allowing water to pass through. Choosing a biofilter media with ample surface area will maximize biofiltration capacity to keep ammonia levels in check.

When choosing a filter, it’s important to select one that is rated for at least the capacity of your tank. In fact, turtles benefit from a filter capacity that is as much as 2-3 times the size of the tank, since they produce more waste than other aquatic reptiles and amphibians. Another thing to be aware of when selecting a filter is that strong currents or excessive aeration in the water can harm small amphibians, like salamanders and newts. For this reason, gentler under-gravel filters or inside corner filters are sometimes recommended for tanks that contain more delicate types of amphibians.

Regardless of the type of filter that you choose, be sure to regularly clean visible debris from your tank. For turtles, it’s best to remove visible feces daily. Additionally, mechanical filtration media should be cleaned at least once per month, generally along with a water change to make sure that solid wastes are removed from filter media before they break down and release ammonia.  To avoid disrupting beneficial bacteria, biofiltration media should be rinsed gently in tank water when necessary.

Water changes

Even with good biofiltration, an aquatic reptile or amphibian tank will still need to be refreshed through periodic water changes. This is because nitrate will tend to build up in the water as the product of the nitrogen cycle. While nitrate isn’t nearly as toxic to reptiles and amphibians as ammonia or nitrite, nitrate levels should still be kept below 40 parts per million (ppm).

To maintain good water quality, most amphibians require 25% water changes every other week. Compared to other aquatic and semi-aquatic animals, turtles produce more waste and typically require a weekly water change of 30% to 50%. Your exact water change schedule will depend upon tank size, how densely your tank is stocked, what species you keep, and other factors. Be sure to do regular water quality testing to determine how often your tank needs a water change. Using high quality filtration media may help to reduce the frequency of water changes by helping to convert some nitrates to innocuous nitrogen gas.

When doing a water change, be sure to use water that is properly conditioned for your tank. Often, tap water contains chlorine or chloramines, which are not only toxic to reptiles and amphibians, but will also kill off beneficial bacteria and lead to dangerous ammonia spikes. Some people choose to dechlorinate their tap water by leaving it out to age for a day or two. While this can be effective for chlorine, this method does not remove chloramines, which many municipalities are now using instead of chlorine. Thus, the best option is to test any water you plan to use in your aquatic reptile or amphibian tank and use a water conditioner product as necessary to remove chlorine, chloramine, ammonia and/or heavy metals.

Using MarinePure® for reptiles and amphibians

Good water quality is essential for any aquatic animal, including reptiles and amphibians. Whether your goal is to maintain a cleaner environment for your turtle, or ensure consistent water quality for sensitive amphibians, MarinePure® biofilter media can help.  MarinePure® offers advantages over other biofilter media by providing more surface area to house more beneficial bacteria, a continuous pore structure to enhance water flow, and anoxic zones to support conversion of nitrates to nitrogen gas. As a result, MarinePure® helps to support better, more consistent water quality for healthy animals, and allowing your tank to go longer between water changes.  For more details on how t use MarinePure in you system, please see this blog.

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