Owning killifish is so much fun that many people want more of them. You can always go buy more killifish from the store, but perhaps you’re interested in breeding them instead.
Breeding fish is something that you need to learn about to get good results. If you want to breed killifish successfully, you must approach things the right way.
Below, you’ll learn all of the details. You’ll learn how they breed and what you need to do as a fish owner to help them.
After reading all of the information, you should feel confident enough to breed killifish. If you put in the effort and things go well, you should have killifish fry to care for soon enough.
Are Killifish Livebearers?
Most killifish aren’t considered to be livebearers. Some people mistakenly think that they are livebearers, though.
This is because they often require the use of a spawning mop to be able to breed in captivity. The majority of killifish lay eggs.
There is an exception to this that you should know about. A type of killifish known as the least killifish is considered to be the smallest known live-bearing fish in the world.
These fish are easy to breed. You don’t have to do anything at all except care for the fish as usual.
So long as the least killifish are kept in a fish tank with the right water parameters, breeding will be simple. You need to make sure that you have one male and one female fish in the aquarium.
Interestingly, these types of killifish produce newborns that are fairly big and capable of taking care of themselves. So you don’t have to worry about the parent fish eating the babies that are born.
The other types of killifish that you’ll learn about below are much different. It’s just good to know that there is one type of livebearing killifish out there that you can buy for your fish tank if you’re interested.
There’s also a caveat to this piece of information. Although these fish have killifish in their names, they’re not considered to be true killifish.
That might be a bit confusing to some, but you’ll learn about true killifish below. Even if the least killifish aren’t true killifish, they can still be fun to own.
Do Killifish Lay Eggs?
Yes, killifish do indeed lay eggs. Killifish are defined as a type of egg-laying tooth carp. They’re related to live-bearing tooth carp such as platies, guppies, swordtails, and mollies.
Despite being related to live-bearers, killifish have a unique means of reproduction. Many of these fish lay their eggs on the roots of floating plants.
In captivity, people generally place spawning mops in the tank to take the place of the floating plants that these fish use in the wild.
There are also killifish who are bottom spawners. They will bury their eggs deep in the substrate.
How Many Eggs Do Killifish Lay?
How many eggs a killifish will lay depends on various factors. There are differences based on the species of the fish that you’re talking about.
Most types of female killifish will lay between ten and thirty eggs at once. Many killifish types become sexually mature at an early age because they have short lifespans.
There are some killifish that can lay as many as 150 eggs at once. The golden wonder killifish is a great example of this.
So you need to look up specific information about the type of killifish you own to know what to expect. It could be anywhere from 10 eggs to 150 eggs, depending on which fish you purchased.
What Do Killifish Eggs Look Like?
Typically, killifish eggs are going to appear to be slightly translucent. They’ll look as if they’re almost clear.
You don’t want the eggs to look white or opaque. This means that the eggs aren’t viable and that something went wrong.
It could be that the eggs weren’t fertilized properly. There’s nothing you can do to save eggs that look this way.
How Long Do Killifish Eggs Take to Hatch?
How long killifish eggs will take to hatch will depend on the type of killifish you’re dealing with. Earlier, you learned that some killifish lay their eggs on floating plants.
These types of killifish are referred to as egg-hangers. Eggs that have been laid by egg-hanging killifish take approximately three weeks to hatch.
Bottom-spawning killifish bury their eggs. These eggs take a longer time to hatch.
The eggs need to remain in the substrate material for around three months. These fish lay their eggs this way because they go through drought periods in the wild.
Some killifish live in areas where the bodies of water dry up for periods each year. So they have short life cycles and bury their eggs deep to help them survive until the water levels rise again.
So these eggs go through a different process. It’s a distinction you want to know about when choosing which fish you’d like to buy for your tank.
How to Hatch Killifish Eggs
The killifish eggs that are buried in peat moss for months hatch differently than the ones laid by egg-hangers. With egg-hangers, you just need to wait three weeks, and the eggs will hatch so long as the conditions in the tank are appropriate.
For the eggs that are buried in peat moss, they must stay in the peat moss for around three months. The amount of time that the eggs need to remain buried will differ depending on the species that you’re talking about.
The peat moss should be removed from the tank. You can store them in a freezer bag and write the collection date on the bag.
This will tell you when you collected the eggs so you’ll know when three months have passed. You’re supposed to keep the eggs in a room-temperature location for months.
Find a room temperature location for the eggs that won’t expose them to strong sunlight. You put them in a small container and add water to the peat moss when you’re ready to help them hatch.
Check the container every few days to see if there are changes in the eggs. Eventually, you should see the eyes of the little fish start to form.
This is when you want to wet the peat moss and put your eggs into tubs of water. This should hatch the fish the rest of the way.
It sounds more complicated than it actually is. People commonly sell killifish eggs and ship them to people who wish to watch the eggs hatch.
Storing the peat moss at room temperature and adding water to help the eggs hatch isn’t difficult. Eventually, you’ll need to put the baby killifish in a small fish tank, though.
Do Killifish Eat Their Fry?
Sadly, it’s common for killifish to eat their fry. They will also eat their eggs.
Killifish are carnivorous fish that will eat fish that are small enough to fit in their mouths. This includes their own offspring.
If you wish to protect the killifish fry, it’s best to raise them in a separate tank. This will allow you to care for the killifish fry and keep them from getting gobbled up by their parents.
It’s also wise to remove the eggs from the tank (or put the parent fish in a different tank) once they’ve been laid. You don’t want the eggs to get eaten either.
This is a normal thing for many types of fish. Killifish certainly aren’t the only types of fish that eat their own young.
Killifish Breeding Setup
A killifish breeding setup doesn’t need to be complicated. You just need to have a small tank where the two killifish can breed.
You need to put one male and one female fish in the small tank. Ensure that the conditions are optimal for whatever type of killifish you’re caring for.
The exact water parameters will differ slightly depending on which killifish type you own. So it’s important to look up specific information.
The killifish will lay eggs when the conditions are right. They’ll be encouraged to spawn and will lay eggs in whatever way their species is supposed to.
For egg-hangers, you’ll need to buy a spawning mop to place in the fish tank. This is there to simulate floating plants that these fish use in the wild.
The egg-hangers will lay their eggs on the spawning mop. Once the eggs have been laid, you’re supposed to remove the parent fish from the small tank.
Three weeks later, the eggs will hatch. The basics aren’t very difficult when caring for egg-hangers.
Caring for bottom-spawning killifish eggs will be slightly different. You must provide the fish with a peat moss substrate layer that is deep enough.
How deep the substrate layer needs to be might vary based on the species. You have to produce the right conditions in the tank to make the fish want to lay eggs.
The fish will bury their eggs, and then you’re supposed to remove them from the tank. You then put the parent fish back in the main tank.
You’re supposed to drain the water from the tank now. These killifish eggs are meant to go through a dry period.
Earlier, you learned that hatching these types of eggs typically takes around three months. Once again, this is a situation where the exact hatching time will differ depending on the species.
You’re supposed to keep the eggs in a room temperature setting without exposing them to strong sunlight. Then you add water when the time is right to help the eggs hatch.
Eventually, you transfer the eggs to a little fish tank. These fish are rather small when they hatch and can be kept in small containers for a little while.
How to Breed Killifish
Breeding killifish involves setting up a small tank where they can spawn. You want to ensure that you have both a male and a female killifish.
Typically, male killifish are slightly larger and more colorful. Females have plumper bodies and are visibly duller than males.
This is an easy way to pick out one male and one female fish when going to a pet store. However, most recommend keeping one male killifish with three females.
Once you have a small tank ready, you need to ensure that the water parameters are right. Set the water parameters to whatever they need to be to encourage spawning.
You can’t rely on general information for this. The water parameters are specific to each species, and there are many types of killifish that you can choose from.
Egg-hangers will lay eggs on floating plants in the wild, but you can replicate this by using a spawning mop in the fish tank. Bottom-spawning killifish need peat moss as the substrate material, and it must be deep enough for them to lay their eggs.
Once the eggs have been laid, you can return the parent fish to the main tank. You don’t want to keep them in the tank because these fish will eat their eggs.
Egg-hangers take around three weeks to hatch. Bottom-spawning killifish eggs need to go through a dry period and must remain buried in the peat moss for around three months.
You add water to the peat moss when the time is right to help the eggs hatch. This is how you breed killifish in captivity.
As you can see, the methods differ depending on the type of killifish that you buy. If you wish to keep things simple, it’s wise to buy egg-hangers such as golden wonder killifish.
Easiest Killifish to Breed
Golden wonder killifish are among the easiest to breed. This is going to be one of the best fish to buy if you want to have a simple time.
It helps that these killifish are among the most common. You can easily find these fish being sold in pet stores locally.
Any type of egg-hanger will be easy to breed overall. They don’t require as much effort as the bottom-spawning killifish.
When caring for egg-hangers, you simply need to get the water parameters right to encourage breeding. The eggs take three weeks to hatch.
Remember, to breed these fish, you must use a spawning mop. You can get what you need at most stores that sell fish and aquarium supplies.
Jeff has always enjoyed having pets, but as a child, he was drawn to his family’s fish tank. Being able to maintain a small ecosystem and observe the behaviors and interactions in the underwater world peaked his interest early on and has kept him hooked until this day. On Avid Aquarist, Jeff shares everything he’s learned about helping aquatic life survive and thrive in a home aquarium.