Why Does My Turtle Smell Like Fish?

Dealing with pet odors is never any fun, especially when you aren’t quite sure what’s causing the smell. Luckily, when it comes to unpleasant turtle scents, there are a few common causes that you can easily get to the bottom of.

So why does my turtle smell like fish? The answer is that turtles themselves don’t actually produce bad smells; any stench is typically a result of their tank being dirty. If you can identify the source of the smell and then thoroughly clean your aquarium and turtle, the fishy smell should completely disappear.

Read on to find out exactly what’s causing your tank’s nasty smell and how to eliminate it. Make sure to take a look at our advice on cleaning and maintaining your aquarium and turtle as well to ensure the smell doesn’t come back!

What Could Be Making My Turtle’s Tank Smell?

If your turtle smells like fish, that’s a sign that their tank definitely needs some attention. Even with regular maintenance and cleaning, it’s possible for different odors to arise. There are a few different reasons why the aquarium might smell less than fresh.

Old Food

If there’s old food floating around in your turtle’s aquarium, it’s very possible that it can cause a foul smell that may then stick to your turtle. Turtles often drop excess food, and it ends up in the water. It can actually destroy the tank’s filter over time, which will only make the smell worse.

Try not to overfeed your turtle, and if you do notice excess food in the tank, remove it right away. As long as you do this regularly, the smell should lessen or disappear completely. Cleaning out any food that happens to be floating around will also keep your tank’s filter running for a longer period of time before it needs to be replaced.

Dead Skin

Turtles are similar to snakes in that they shed their skin. Your pet turtle will frequently shed the skin on their shell. This is called “molting.” You’ll notice sheets of paper-like skin that peel off of your turtle’s shell and then float around in the tank’s water. This is completely normal, but it is necessary to clean it up.

This dead skin or molt can clog the tank’s filter and cause a nasty smell. Be sure to clean the tank periodically, and skim the water to get rid of any dead skin on a regular basis.

Excessive Waste

As long as you clean your turtle’s tank regularly and thoroughly, excessive waste shouldn’t be a problem. But it’s no surprise that a buildup of waste can lead to an unpleasant smell. As the waste begins to decompose in the water, it will give off a bad stench that your turtle may also carry as a result. 

Rotting Plants

The plants in your turtle’s aquarium may be to blame if you notice a nasty smell. You should be able to identify dead plants pretty easily. They often look slimy and turn dark brown or black. These rotting plants can ruin the water quality of your turtle’s tank and should be removed as soon as possible. Algae can also rot and cause a musty odor.

Living plants don’t give off bad smells, so make sure that any plants in the tank get plenty of nutrients and light and you should be just fine! 

Dirty Filter

Old food, dead skin, excessive waste, and rotting plants can all be sucked up by your tank’s filter, so it shouldn’t come as too much of a surprise that your filter may be the cause of any unpleasant smells you notice. Often, you’ll find more sludge inside the filter than in the tank itself!

Cleaning your aquarium’s filter should already be a part of your regular maintenance routine. When you change out the water in the tank, give it a thorough rinse in the water you removed. This will prevent any good bacteria in the filter from being killed, and it should lessen the smell or make it disappear completely.

Substrate Problems

Problems with your substrate usually won’t present with a fishy smell, but instead with more of a rotten egg odor. This is because bacteria can build up in the substrate and be released as gas that travels through the water in the tank.

As always, cleaning your tank on a regular basis is a good way to take care of this problem. You can purchase a deep gravel vacuum or stir the sand in the substrate to keep bacteria from growing.

Water Conditioner

Many turtle owners add a water conditioner to their aquarium when changing out the water. However, this water conditioner may actually be the source of the bad smell! Try to avoid water conditioners that contain sulfur because they can make your tank smell like rotten eggs.

How to Remove Smells From Your Turtle’s Tank

Make sure to take your turtle out of the tank while cleaning because it can be a very stressful situation for them. You’ll want to get a clean sponge to clean any algae and bacteria from the sides of the tank. A magnetic sponge is especially helpful in this situation. 

Next, unplug the filter and heater. Remove about three-fourths of the water from the tank, but don’t get rid of it just yet. Clean the filter in the water from the tank to avoid killing any good bacteria living on it. Then fill the tank back up and plug everything back in, and you should be good to go!

How to Clean Your Turtle

Even though the smell isn’t caused by your turtle, your pet can definitely pick up smells from their dirty aquarium. This means that after you identify the source of the smell and clean your turtle’s tank, you’ll also need to give your turtle a good washing. Otherwise, the smell will return and you’ll be back to square one.

All you’ll need to clean your turtle are a soft toothbrush and a container large enough to hold your pet. Make sure the toothbrush is new and bacteria-free. You can use your sink instead of a container for your turtle, but you’ll have to thoroughly disinfect it afterward.

Step 1

The first step is to wash your hands. Don’t apply any lotion or hand cream, and make sure that you’ve rinsed off any soap. Next, add water to the container. It should be about the same temperature as the water in your turtle’s tank. Make sure not to add any soap to the container.

Step 2

Now it’s time to clean your turtle. Place it in the container and grab the toothbrush. You’ll want to use fresh water to dip the toothbrush in periodically. Pick up your turtle, holding it by the sides. Avoid using too much pressure. Start cleaning your turtle’s shell from the edges and use small circular motions.

Step 3

Once your turtle’s shell is clean, gently go under the edges of the shell with the toothbrush. It’s important to pay close attention to this area because algae and bacteria often build up there.

Step 4

Just like cleaning the top of the turtle’s shell, use small circular motions to clean the bottom. Don’t scrub vigorously as this can hurt your pet.

Step 5

Once your turtle is nice and clean, place them under a good light source like the one from their basking area. Give them a good inspection to make sure you haven’t missed any dirty spots. If you do notice an area that needs more cleaning, you can do a simple spot cleaning instead of repeating the entire process.

Step 6

Make sure to throw away the toothbrush after cleaning your turtle–it will have tons of bacteria on it! You can either disinfect the container you used to hold your turtle while cleaning it, or you can simply throw it away.


If your turtle smells like fish, the most common culprit is a dirty aquarium. If you maintain a clean tank, you should be able to prevent smells in the first place. But if you’re struggling to figure out where the smell is coming from, look at your tank’s filter, old food, dead skin, waste, rotting plants, and the tank’s substrate. It’s likely that one of these is the cause of the stench.

Once you’ve identified the source, you’ll want to thoroughly clean both the tank and your turtle to keep the smell from reappearing. Although a fishy-smelling turtle is unpleasant, it can usually be fixed with some simple cleaning!





I’m Devin Nunn, an average joe that just so happens to have a deep love and passion for everything to do with reptiles. Because taking care of them for the vast majority of my life wasn’t fulfilling enough, I decided to begin educating others about them through my articles. read more...