No, they cannot. Despite both being freshwater fish, the neon tetra and goldfish cannot live together for a number of different reasons. Neon tetras are perhaps the most popular sub-species of tetra due to their vibrant coloration and infectious personalities. However, goldfish are also an incredibly popular freshwater fish, so, why can't they live together in perfect harmony?
Why Can't Neon Tetras Live with Goldfish?
Tetras, and in particular, neon tetras, cannot live with goldfish for an abundance of reasons, with the most common being that tetras naturally live in warm environments and goldfish naturally prefer a cooler tank.
Neon tetras and goldfish are incredibly different fish from one another, with many different requirements, making it almost impossible to house them both together. Let's dig into all the details to find out why.
Due to their different natural habitats, all tetras require much warmer waters than goldfish do. With tetras living their healthiest in waters between 75-78°F (24-25.5°C), and goldfish requiring a water temperature of 68-74°F (20-23°C). Additionally, tetras tend to produce far less waste and are incredibly sensitive to water changes, whereas goldfish produce an abundance of waste, requiring regular water changes and tank maintenance.
Keeping healthy and happy fish is mainly down to their environment and more specifically, the quality and temperature of the water in their home. Being tropical fish means that tetras naturally require warm waters, and goldfish not being tropical fish means the opposite.
Due to their hardy nature, it is possible to try and adapt your goldfish to warmer waters, but they do grow much quicker in hotter temperatures, and you will risk them outgrowing their aquarium.
Another big risk in their growth is that they could turn on your tetras, should they become big enough to consume them. Your tetras will notice the goldfish growing in size and will begin to hide in your tank to avoid this from happening.
The problem for the tetras is that they will become far less active and more stressed out, and both of those things will compromise their health. It can also split up your school of tetras due to them being incredibly social fish, staying within a school of 10 to 15 other tetras.
Your Goldfish May Eat Your Tetras
Due to goldfish being omnivores and also due to them eating almost anything that they can fit in their mouths, you run the risk of them treating your neon tetra as a tasty snack! However, this is not to say that goldfish are aggressive, coldblooded killers, it is quite the opposite actually. But, if they are large enough, and your tetras are small enough, don't be surprised if your goldfish try and eat one or two.
They are usually hungry and will easily mistake your tetra as food. Even if you feed your goldfish correctly and provide plenty of plants to eat too, they still might just eat your tetras as there seems to be no particular pattern when it comes to goldfish snacking on other tank inhabitants. There are many different types of goldfish, however, their food consumption and appetite to eat almost anything they see never changes!
Different Aquarium Environments
Most hobbyists wish to run a beautiful and effective aquarium, where their fish can live a happy and healthy life with as little upkeep as possible. However, this is not the case when you own goldfish, and it is why tetras and goldfish are incompatible tank mates too as they both thrive in totally different environments.
Goldfish are renowned for creating an incredibly messy aquarium environment through their mass waste production. Goldfish will eat pretty much anything and everything they can, which in return creates a messy living environment and a lot of waste within their fish tank. They will also swim around the tank, nibbling at various things to test whether they are edible or not, decorations, plants, and substrate. All of this requires frequent water changes and tank maintenance.
Whereas tetras are small and clean fish, who usually keep themselves to themselves and create minimal mess and food waste. Frequent water changes are not good for tetras, they need more consistent and stable environments, so, by cleaning and maintaining their tank all the time, you will cause them some harm.
Goldfish are Not Tropical Fish
Tetras are tropical fish and goldfish are certainly not. As mentioned previously, the temperature requirements are in different ranges between tropical fish and non tropical fish, however, there is a lot more that goes into it.
One of the main differences is the resistance to diseases. Goldfish are far more susceptible to disease when residing in warmer waters, and also tropical fish, like neon tetras can carry diseases which can be fatal to goldfish.
Goldfish also have completely different diets to tetras due to their natural habitats being so different. Goldfish cannot digest food that has not been specifically made for them, this is due to goldfish not having actual stomachs, which makes them struggle to digest food.
You will need to feed your tetras tropical fish food, and due to goldfish eating anything they can, they will likely eat some of that too, which will cause them problems down the road. Goldfish should be specifically fed goldfish flakes or goldfish pellets.
Both of these fish species are incredibly sociable, with tetras being community fish, living their best and happiest lives in schools of 10 to 15 fish. You should never house tetras in groups of less than 6 fish, this is because if they are in smaller groups residing in a community tank with larger fish they could feel threatened which can cause stress. Stress for fish is never good, and usually leads to serious health repercussions and actually causes their color to diminish!
Goldfish are also social fish, but they do not live amongst schools, typically migrating towards other goldfish species. Rather amusingly, a group of goldfish is called a "troubling". The problem with a group of goldfish is that, if they are housed with a school of tetras, you would unfortunately likely witness some of your neon tetras go missing - never to be seen again!
In conclusion, neon tetras and goldfish should NOT live together. They are both incredibly fun and beautiful fish to keep, but there are unfortunately too many factors that suggest they shouldn't be kept together, with the main one being the health and wellbeing of both fish species.
So, by creating a healthy aquarium environment for each fish species and keeping them separately, you can enjoy the benefits of having both fish, just not in the same aquarium.