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Killifish Size (How Big Do Killifish Get?)

Killifish Size (How Big Do Killifish Get?)

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This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

There are so many different types of killifish out there. You might be trying to narrow down which killifish you want to buy for your aquarium.

For some, it’ll be easier to choose by narrowing down the sizes of these fish. Different killifish types will grow to be different sizes.

You might be more interested in smaller types of killifish if you don’t have a lot of room in your home. Or perhaps you want a larger killifish that will look great in your tank.

Read on to learn about how big different types of killifish get. Once you’ve read everything, it’ll be that much easier to make a choice about which fish to buy.

How Big Do Killifish Get?

The size of a killifish will differ depending on the species. Some killifish are going to be rather small while others will be closer to medium-sized fish.

These fish aren’t generally that big, no matter what, though. You’re not going to see any killifish that reach twelve inches in length or anything near that.

Most killifish will be somewhere between one and two inches long. Then there are larger killifish that can reach close to six inches in length.

To learn how big killifish can get, you will want to look up information on individual species. This allows you to get all of the information that you need.

Smallest Killifish

Some people say that the least killifish is the smallest killifish that you can find. From a certain point of view, this is true.

However, the least killifish don’t qualify as true killifish. Killifish are defined as an egg-laying species. The least killifish is a live-bearer, and it’s considered to be the smallest live-bearer known to man.

The males grow to be 0.8 inches while the females grow to be 1.2 inches. These fish are rather small, but they’re not technically killifish despite being named as such.

Least Killifish Size

As mentioned above, the least killifish is rather tiny. The males are very small and only grow to be 0.8 inch long.

Females grow to be a bit larger and will reach 1.2 inches in length. These fish are very interesting to own if you’re interested in caring for a live-bearing fish.

Golden Wonder Killifish Size

Golden wonder killifish are fairly large as far as killifish go. You can expect this fish to grow to four inches in length as it continues to mature.

This semi-aggressive fish should be kept in a 20-gallon fish tank. It’s an easy fish to care for, and many people love keeping these fish in their tanks due to their beauty.

How Big Do Clown Killifish Get?

Clown killifish are on the other end of the spectrum when it comes to size. These are small fish that will only grow to be between 1.2 and 1.4 inches long.

Since they’re fairly tiny, you can keep them in small fish tanks. Some choose to keep them in 5-gallon fish tanks, but many argue that they do better in 10-gallon aquariums.

How Big Do Blue Lyretail Killifish Get?

The blue lyretail killifish is another neat-looking fish that is close to medium-sized. It grows to be two and a half inches long at maturity.

Since these fish are semi-aggressive, it’s best to give them space. You’ll find that they do well in 10-gallon fish tanks, but some people choose to keep them in 15-gallon fish tanks as well.

How Big Do Chocolate Lyretail Killifish Get?

Chocolate lyretails are a bit different than the blue lyretails mentioned above. These fish can grow to be between two and three inches long.

Since they’re slightly bigger, it might be best to keep them in a 15-gallon tank. However, it’s common for them to be kept in 10-gallon aquariums as well.

How Big Do American Flagfish Get?

American flagfish grow to be just 2.6 inches long, but they’re quite aggressive. Although they’re considered to be semi-aggressive fish, they aren’t good candidates for community fish tanks.

Give these fish enough space so they can do well in your tank. It’s best to keep them in a 15-gallon fish tank or something larger.

How Big Do Blue Gularis Killifish Get?

Owning a blue gularis killifish will be truly satisfying. These fish are so stunning to look at that they’re now sought-after by many aquarium enthusiasts.

A blue gularis fish will grow to be between three and a half inches and five inches long. So it’s a pretty big fish when compared to many of the other killifish that you’ll learn about today.

How Big Do Red-Striped Killifish Get?

Red-striped killifish are another relatively small type of killifish. They grow to be around two inches long at maturity.

These fish are peaceful, and they’re also rather colorful. They make good options for those who want to put killifish in community fish tanks.

How Big Do Magnificus Killifish Get?

The magnificus killifish is tiny, but it still needs enough space to thrive. These fish grow to be just an inch, but most recommend keeping them in 10-gallon fish tanks.

Owning these fish will be a real treat because of how pretty they are. They really are fish that add color and aesthetic appeal to any fish tank that they’re put in.

How Big Do Blue Notho Killifish Get?

Blue nothos are fairly peaceful types of killifish. They grow to be two and a half inches long in adulthood.

Many people love these fish because of how colorful and fun they are. They have red bodies and blue spots that make them look very appealing.

How Big Do Redtail Notho Killifish Get?

The redtail notho is quite similar to the blue notho fish mentioned above. These fish also grow to be two and a half inches long at maturity, but they have different bodies that help them to stand out from their blue notho cousins.

Both blue nothos and redtail nothos are among the most popular types of killifish to keep in aquariums. You’ll be pleased if you buy some of these fish for your home.

How Big Do Kisaki Killifish Get?

The Kisaki killifish is another type of fish that grows to be two and a half inches long. This carnivorous killifish is peaceful and should be okay in community tanks with compatible tank mates.

It’s also a pretty fish that will look good in small groups. Remember to buy one male and keep it with two or three females.

How Big Do Argentine Pearlfish Get?

Argentine pearlfish are rather gorgeous, but they’re semi-aggressive fish that don’t play well with others. Don’t put these fish in a community aquarium.

They grow to be 2.75 inches long and need to be kept in 15-gallon fish tanks. If you find one of these being sold, it’d be a good fish to purchase so long as you have a bit of experience caring for fish.

How Long Does It Take for Killifish to Grow?

The growth rate of killifish differs greatly between species. This is because there are three distinct categories that killifish fall under.

Annual killifish have to grow very fast because they live in bodies of water that dry up. They’ve evolved to develop fast so they can reach maturity and breed before the body of water dries up.

These fish bury their eggs deep in the ground so they can survive until the water comes back. Since they have accelerated growth, they also die a lot faster.

Some of these fish only live to be eight months old or so. Semi-annual fish are similar, but they live in bodies of water that don’t dry up as frequently.

Non-annual killifish live in permanent bodies of water. They have normal growth rates and are capable of living for several years.

So growth rates are specific to each species of fish. You need to look up individual information to be sure that you know what to expect.

How to Help Killifish Grow

Helping killifish to grow and stay healthy involves caring for them properly. Make sure that the water parameters in the tank are right by checking them regularly.

Test the pH balance of the water using a testing kit. Monitor the temperature.

Continue to feed the fish high-quality foods. Make sure that the fish eat a healthy diet that gives them all of the nutrients that they need to thrive.

You can’t make small killifish grow larger than normal, but you can help them to reach maximum growth potential and stay healthy. Handling the basics is all that’s required.

Note that keeping the fish in tanks that are the right size will be important as well. Cramming a fish into a small tank can inhibit its growth.

Final Thoughts

Knowing more about how big these fish get should be beneficial. Now you know that most types of killifish are fairly small.

Many grow to be between one and two inches long. Some will be larger and might be close to six inches long.

There are a lot of fish that fall in the medium-sized range as well. Popular killifish types, such as the American flagfish, grow to be 2.6 inches long.

Choose the fish that appeals to you the most. Be sure to care for them right so they can grow strong and remain in good health.

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