Also cardinal tetras are not the most commonly kept species of tetra within the fish keeping hobby, they are seeing some growth in their popularity and many people look to breed their cardinal tetras to successfully grow their own fish from fry to adults.
With so many people often making easy to avoid mistakes, we have decided to publish this article to try and help as many of our readers successfully raise their cardinal tetra fry.
In the average tank setup, the survival rate of cardinal tetra fry will be lower than 20%, often very close to 0% in a community tank with plenty of predators.
That said though, if you follow our tips and tricks below, you should be able to increase the survival rate of your cardinal tetra fry to well over 70%, often closer to 80%.
Not only do our tips and tricks improve the survival rate of your cardinal tetra fry but they can often make your life much easier when caring for the fry too.
Some of our tips can also help to reduce the costs required to raise your cardinal tetra fry helping to keep your costs as low as possible too!
Use A Breeding Tank If Possible!
If you’re planning to breed cardinal tetras and raise the fry, then using a breeding tank is going to be your best option for success.
A breeding tank is a smaller aquarium which is used just for breeding and raising cardinal tetra fry in an environment that is free from predators.
Although cardinal tetras are less likely to eat their own young due to being a schooling fish, the parents can turn around and eat their own eggs and fry.
The chances of this are higher if the parent cardinal tetras are stressed or anxious but they can still make a solid dent in the potential progress of their own offspring, especially during the egg stage.
One of our favourite breeding tank options for cardinal tetra fry is a cheap 10 gallon tank that is quick, easy, and reliable to use. You can also use an older aquarium tank that you are no longer using as a breeding tank if needed too.
If You Can’t Use A Breeding Tank, Use A Breeding Box!
If you can’t use a breeding tank, the next best solution is to use a decent breeding box. A breeding box is a smaller transparent aquarium or plastic box which is placed into your existing cardinal tetra tank to offer protection for the fry.
The breeding box should be placed towards the back of the cardinal tetra tank so that the fry have plenty of time to sense when predators are close and can easily dart into their breeding box for safety.
We recommend a breeding box that is at least 10 times the size of a cardinal tetra so that they can comfortably hide away if needed.
A breeding box is usually only effective until the six weeks of age point and then after that, your cardinal tetra fry may not be able to get into it quickly.
This is why we always recommend a separate breeding tank if possible to allow you to keep your cardinal tetras in there until they are large enough to return to their main tank.
Offer Plenty Of Places To Hide In A Community Tank!
If you’re keeping cardinal tetras in a community tank, then it’s important to offer them plenty of places to hide away and escape from predators when needed.
One of the simplest ways that you can do this is by using live plants within your cardinal tetra tank. We recommend that you also consider using cholla wood, fish fry hides, and breeding grass in a heavily stocked community tank too.
They are excellent sources of cover for your cardinal tetra fry while also being quick and easy to remove from the tank once the fry are large enough.
Many people keep their cardinal tetras in a species specific tank so there will only be cardinal tetras in the tank but they can still eat fry of their own species even though many people say that they don’t…
Offer Your Cardinal Tetra Fry A Suitable Food Source!
Most people are surprised by just how small cardinal tetra fry actually as as they are tiny and they can be very difficult to see until they are around one week old.
Due to being so small, their jaws are tiny so their food options are limited with all species of fish fry often being fed an unsuitable diet in many cases resulting in the fry starving within their fist week.
Vinegar eels can work but they are not as reliable as microworms. Some people also just grind fish flakes up into a tiny, fine dust like food and this can work but it is not reliable.
Some cardinal tetra fry will not go to the surface to feed and can still have issues with ground up flakes making miroworms the best option.
Once the fry get larger, you can add crushed up mysis shrimp to their diet before eventually putting them on the same food as your adult cardinal tetras.
Select Bright Male Cardinal Tetras And Fat Female Cardinal Tetras For Breeding!
If you want to ensure that you get plenty of cardinal tetra fry, then you need to carefully select the cardinal tetras which you are going to use for breeding.
Although all cardinal tetras should be able to produce fertilized eggs, there are some tricks that you can use to increase your fertilized egg yields.
Try to chose the vibrantly colored male cardinal tetras with the larger fins and the fatter female cardinal tetras from your collection.
Not only do the brighter colored males have a higher chance of getting the female to continuously spawn her eggs but the fatter females often carry more eggs.
The normal egg yields per spawn for a healthy female cardinal tetra is between 150 and 500 eggs but this simple trick can consistently keep the egg yield closer to the 500 mark.
The brighter colored males often have no problem quickly fertilizing such a large number of eggs too so this often overlook step that usually takes a couple of minutes can double or even quadroupale the number of fertilised eggs that you start with.
Remove The Female Cardinal Tetras As Soon As They Have Spawned!
If you are going with a breeding tank setup that we highly recommend, we would recommend that you remove the female cardinal tetras after they spawn their eggs.
Although it is less likely that a female cardinal tetra will eat cardinal tetra fry, they will eat surprisingly large numbers of cardinal tetra eggs, even if they are her own eggs that she literally just spawned…
Once you are confident that your female cardinal tetras have spawned the bulk of their eggs, remove them from the breeding tank and place them back into their main cardinal tetra tank.
We would also recommend that you remove any cardinal tetras which have not spawned as they are likely to eat cardinal tetra eggs as some of your female cardinal tetras may choose to not spawn even in optimal conditions.
Remove The Male Cardinal Tetras When The Eggs Have Been Fertilized!
Once the male cardinal tetras have fertilized the eggs, we would recommend that you remove them from the breeding tank if possible. Not only will the male cardinal tetras eat their own fertilized eggs but they also have a higher chance of eating cardinal tetra fry too.
We know that it can be very difficult to know if your male cardinal tetra has fertilized the eggs or not so some people just go by the two day rule.
This is based around the theory that once you remove the female cardinal tetras from the breeding tank, the male cardinal tetras are left in for 48 hours and then removed no matter what.
Feed Your Cardinal Tetra Fry Three To Five Times per Day!
All species of fish fry have a huge amount of growing to do in their first month of life so they require frequent feeding sessions. The cardinal tetra fry are no different and will need to be fed 3 to 5 times per day.
The cardinal tetra fry can be very small when they first hatch out so we would recommend getting some live foods which are small enough for them to eat. microworms or vinegar eels as well as specialty fish fry starter food are usually the best options but vinegar eels can be difficult to find in some areas.
We know that people live a busy life these days often preventing people from being able to feed their cardinal tetra fry so frequently. This is where an automatic fish feeder comes in but it won’t work well with live food so you pretty much have to use the fry starter food options for them.
Most people recommend that you risk overfeeding your fry rather than underfeeding and we agree.
Cardinal tetra fry which are not getting enough to eat often have a very hard time developing their cardinal tetra colors and cardinal tetra pattern later on in life while often having stunted growth and lower survival rates.
Maintain Stable And Consistent Water Parameters For Your Cardinal Tetra Fry!
We know that adult cardinal tetras are very sensitive to changes in water parameters but you need to remember that cardinal tetra eggs and cardinal tetra fry are even more sensitive.
This means that you will need to take extra care when setting up your breeding tank and making sure that the cardinal tetra fry have stable and consistent water parameters.
You can use a Water Test Kit to monitor most of your water parameters for cardinal tetra fry but we would recommend testing for ammonia, nitrites, nitrates, and pH levels in the tank on a regular basis.
Water hardness, water flow, and light intensity all plat a role in the survival rate of your cardinal tetra fry too so factor all of this in!
Daily Water Changes Can Be Essential!
We know that cardinal tetra fry are very sensitive to changes in water quality so it is important that you do regular water changes.
The cardinal tetra fry tank should have a 10-20% water change done every day without fail to make sure that they have the best chance of survival.
You might be wondering why we recommend such high water changes when cardinal tetra fry are so sensitive. The main reason is that cardinal tetra fry produce a lot of waste and the high water changes help to keep the tank clean and free from ammonia and nitrites.
We would also recommend doing a larger water change of around 50% once a week as well as a gravel vacuum if you are unable to do the daily water changes. You should also use a water conditioning product on any tap water that you plan to use for the tank to make sure that it is safe for the tank too.
Chlorine from tap water can be lethal to cardinal tetra fry so make sure that you remove it before adding the water to the tank. This is usually much easier than most people initially think it will be and the process doesn’t tend to take long when you are only changing 10-20% of the water in a small 10 gallon tank each day anyway but it can greatly benefit the cardinal tetra fry and help to improve their survival rates substantially.
More experienced fish keepers can integrate various pump and filter setups to reduce the risk due to issues with water parameters but the majority of our readers are generally new to breeding their fish.