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Kidadl Team

AUGUST 06, 2021

19 Fin-tastic Facts About The Gulf Killifish For Kids

Here are some Gulf killifish facts for you to check out - everything from the Gulf killifish embryo, breeding Gulf killifish and Gulf killifish habitat is covered.

The Gulf killifish (Fundulus grandis) is a species of primarily estuarine fishes that can be found along the shores and marshes of Florida, Texas, Mexico, Mississippi, and Cuba. Science tells us that they can handle extremes of salinity, temperature, and oxygen levels in the water. These fishes are beautifully compact and have a very attractive light blue, gray, or green color that can add to the charm of any aquarium. They breed and hatch in native marine conditions between March and September.

These tiny fishes of about 4-7 in (10-18 cm) are omnivores and feed on anything available to them in coastal, marine, and river waters. Their populations have an unequal distribution of males and females.

The Gulf killifish can also be easily distinguished from any other species of the same class due to their short snout, protruding lower jaw, a single dorsal fin, absence of spines in the fins, and a deep caudal peduncle.  It is interesting to note that they are in fact the largest of the eight varieties of killifish that are found in America. If you happen to come across a killifish that is more than 3 in (7.6 cm) in length, you can be quite sure that it is a Fundulus grandis.

If you would like to learn more about fishes and find the perfect pet, make sure to check out our articles about plaice and turbot.

Gulf Killifish Interesting Facts

What type of animal is a Gulf killifish?

The Gulf killifish (Fundulus grandis), like the name suggests, is a fish. While the scientific name, Fundulus grandis (Baird and Girard), complicates things, fishermen are most familiar with these tiny fishes and use them as live bait. If you can want to identify them, look for the single dorsal fin and deep-set caudal peduncle.

What class of animal does a Gulf killifish belong to?

The Gulf killifish as a species is classified as Actinopterygii within the animal kingdom.

How many Gulf killifish are there in the world?

There are no conclusive numbers as to what the populations of Fundulus grandis can amount to, because these fishes have a fairly large litter size and can produce as many as 13,000 eggs annually. Their conservation status is Least Concern and their marine distribution is vast.

Where does a Gulf killifish live?

Gulf killifish are found in various habitats and conditions. While they prefer marshy areas, they are also found in fresh water rivers and coastal areas. This is because the Fundulus grandis is capable of sustaining itself in almost all levels of salinity, whether low in fresh water tributaries, or high in the seas. They can also survive in waters with low oxygen levels which explains why they can be found in a marsh.

What is a Gulf killifish's habitat?

The natural habitat of our tiny friends is in the Gulf of Mexico,  running around Texas to Florida, and in the Caribbean Sea. While these areas see the most dense population of the Fundulus grandis species, their sturdy nature and very diverse diet allows them to inhabit marshes and rivers as well.

Who do Gulf killifish live with?

This species, like most other small fishes, prefers to live in large schools. They are also very friendly with other marine animals, however, the male fishes sometimes tend to be quite aggressive. The large population of each school is also because of the extensive number of eggs that are laid during each spawning season.

However, if you are looking forward to adopting a killifish as your next pet, they would love to have small catfish, black neon tetras, neon tetras, x-ray tetras or rainbow fishes as tank-mates.

How long does a Gulf killifish live?

It is interesting to note that the Gulf killifish has a total life-span of about a year, from hatching to death. The short lifespan helps in balancing the population as they lay such a huge number of eggs annually.

How do they reproduce?

The spawning season for these natives of the northern Gulf goes on from about March to September, and the eggs hatch shortly afterwards. The reproduction takes place in shallow waters, such as in a river or marsh, and the females lay their eggs in the course of three to five days in numbers that range from 20-80. During this season, the females tend to become more aggressive than the males.

What is their conservation status?

The conservation status of these blue-bodied natives of Florida, Texas, Mexico, and the Gulf Coast is of Least Concern. Even in a tank or aquarium, it is unlikely that your killifish will be attacked by any of its tank mates.

Gulf Killifish Fun Facts

What do Gulf killifish look like?

Gulf killifishes have characteristics that run fairly uniformly throughout the species. The upper portion of their body is usually of a light blue, gray, green, or muddy yellow color and the belly area is of a pale yellow complexion. These fishes are fairly tiny and range from about 3.9-7 in (10-18 cm). Female Fundulus grandis ​have a larger body and anal fins than the male counterpart

These small marine fishes are characterized by their blunt head and a slightly protruding lower jaw. They are also seen to have a deep set caudal peduncle which is the part right before where their anal fins start, and a single dorsal fin. Being a small species, they do not have spiked fins on their body.

Gulf killifish find their native land in Florida, Texas, Gulf Coast, Mexico, the Mississippi River and any brackish marsh.
* Please note this is an image of an striped killifish, not a Gulf killifish. If you have an image of a Gulf killifish please let us know at [email protected]

How cute are they?

It is safe to say that these natives of the Gulf Coast are very cute. This marine species of fish has a deep caudal peduncle and a yellow colored body.

How do they communicate?

The entire genus of killifish exhibits a rather interesting mode of communication. Science suggests that they communicate through the changing color of their fins and bodies. The male killifish can often be seen to have developed different colored spots on its anal fin. It does so in order to communicate with its friends.

How big is a Gulf killifish?

Fundulus grandis is a fairly small species. These top minnows can be as tiny as 3.9 in (9.9 cm) long and reach a maximum length of 7 in (17.78 cm). The small size and raging populations of Gulf killifish allow them to be used efficiently as bait by fishermen.

How fast can a Gulf killifish swim?

The entire genus Fundulus is characterized by the speed of these fishes. All eight species of killifish are fast-swimming predators and can definitely win a race against the larger fish in your aquarium.

How much does a Gulf killifish weigh?

You will be surprised to know that the Fundulus grandis is such a small species that it only weighs about 0.01 lb (4.53 g), even the heaviest in the school will only be 0.02 lb (9.07 g). This adds to the list of reasons why they serve as amazing live bait.

What are the male and female names of the species?

While the male and female Gulf killifish can differ in length by about 2.36 in (6 cm), different names are not designated to the two sexes.

What would you call a baby Gulf killifish?

This oviparous species does not have any special name assigned for the babies either, but you can always lovingly call them by one of the common names such as bull minnow, mud minnow, or cacahoe.

What do they eat?

Fundulus grandis is a species of omnivores which means that the species has a very varied diet. They feed on algae, underwater weed, insects on the surface of water, grass shrimps, crabs, and small fish. The range and variety in their diet makes them a fairly hardy species that can accept many different habitats.

Are they poisonous?

If you are worried about being poisoned by a Gulf killifish, be assured that they pose no such threat. These are fairly harmless fishes, both for their neighbors, tank-mates, and humans.

Would they make a good pet?

It is common practice to have a killifish or two in domestic aquariums. While male Gulf killifish can sometimes be violent towards its own species, the females are completely peaceful and can be kept in large numbers. This fish also has a colorful body which will add to the beauty of your aquarium.

Did you know...

Our cute aquatic natives of Florida, the Gulf Coast, and the Gulf of Mexico not only help fishermen at their work, but also serve brilliantly in fighting the mosquito population that inhabits marshy regions. Gulf killifish feed on mosquito larvae and help to keep the ecosystem balanced.

It is also interesting to note that Fundulus grandis, before laying eggs, begin to show color changes in their fin and body. The male fish changes its color to a bright blue with shiny spots on the body and red spots on their anal fins.

If you can want to identify them, look for the single dorsal fin, anal fin, and deep-set caudal peduncle.

What is the largest killifish?

It might sound funny but the largest Gulf killifish (Fundulus grandis) that has been observed to date was only 7 in (17.8) long. The fact that this species is the largest of the eight species of killifish makes you wonder how small the other species are.

Why are killifish endangered?

While the conservation status ofGulf killifish states that they fall into the category of Least Concern, recent oil spills and consequent studies observe a few adverse affects on the life of this species. Scientists observe that the eggs that come into contact with oil hatch later than than the normal eggs, and that the fishes that emerge from the former are not only smaller, but also have certain heart-related troubles. Development in science also suggests that this species is also endangered by sharp drops in temperature, as was witnessed during the winter of mid 2010s.

Apart from that, nothing endangers Fundulus grandis and they play their own role in the food chain as both predator and prey.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other fish from our brown trout facts or black sea bass facts pages.

You can even occupy yourself at home by coloring in one on our free printable Gulf killifish coloring pages.

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