You might think of reptiles as not having much odor at all, and certainly a wet turtle doesn’t smell anything like a wet dog, but they can still produce unpleasant smells. It is also possible for a tank to develop a bad smell from causes other than the turtles, for example with stale or rotting food.
Those tiny turtles sold in pet stores grow rapidly, with even the smallest species commonly available growing to at least 6 inches across. Many grow to twice that size or more. This means that only the biggest tank is going to be suitable for your turtles. Turtles produce a lot of waste and a tank that is too small will become unhygienic and smell awful rapidly.
Chances are you’ll need to clean the tank at least once a week and remove debris daily. Use tongs to remove uneaten food and feces from the land area and a gravel cleaner and bucket to siphon debris from the water. If the water area is just a bowl, change the water daily. Conduct partial water changes at least once a week if the tank has a large water area or clean the tank completely if it is a terrarium. Because turtles have waterproof skin and breathe air, you can remove more water at a time than you would for an amphibian or fish. Turtles are not so sensitive to water parameters, although you must still use dechlorinated water. If the tank still smells despite a thorough cleaning regime, increase the frequency of the cleaning or water changes.
You need a powerful aquarium filter for turtles. Simply swapping the filter you have for a bigger, more efficient one might reduce smells. Remember to change the filter media frequently, as this is a place where smell-producing bacteria multiply.
Avoid Commercial Cleansers
Don’t use scented or deodorizing cleaning products in an effort to mask the smells. These products might be lethal to your pets. The same goes for air freshener -- do not use it in the same room as the turtle tank. The strongest chemical you should use to clean the tank is a reptile-safe disinfectant and don’t forget to rinse thoroughly afterward.
Some turtles grow so big that they are never going to live comfortably in a tank in your living room, and the tank is never going to smell nice. In these cases, you have a couple of options. You can transfer the turtles to a backyard pond, but this is only an option if the climate is suitable for the species and the pond is securely enclosed. The other main option is to rehome the turtle with somebody who has the necessary facilities. Animal parks, reptile rescue sanctuaries, zoos and some committed hobbyists may be able to take proper care of your pets.
Releasing the turtle outside is not an option unless he both belongs to a species native to your area and was wild-caught locally in the first place. Invasive species cause serious problems for native wildlife and even an individual of a native species from another area carries different genes. Note that turtles caught outside may be from an invasive species, not a local one. Basically, the only time release is a responsible decision is if you or a child caught a small native turtle outside and the turtle has now grown.
Judith Willson has been writing since 2009, specializing in environmental and scientific topics. She has written content for school websites and worked for a Glasgow newspaper. Willson has a Master of Arts in English from the University of Aberdeen, Scotland.