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Striped Killifish (Fundulus Majalis) Care Guide

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Small but colorful fish for your aquarium? Killifish is undoubtedly a rarely known gem in the aquarium trade industry. Striped killifish is no ordinary killifish as they have adorable stripes that make them distinctive and attractive in a community tank, not to mention their unique behavior.

Striped killifish is a small fish species largely found in the Chesapeake Bay. They only grow up to 8” so they can fit a 20-gallon aquarium. They can live well in a community aquarium for up to five years.

Species Overview

Level of CareEasy
AppearanceMale has vertical bars while females have horizontal bars. Both have silvery-olive body coloration.
Life ExpectancyUp to 5 years
SizeUp to 8 inches
Tank Size20-gallon or larger
Tank EnvironmentShallow water flow with plantation
Tank MatesKept in pairs or groups for a species tank Carefully selected tank mates for the community tank

Striped killifish or fundulus majalis is the member of the family Cyprionodontiadae and they’re relatives of those platies, swordtails, guppies, and mollies.

The biggest population of wild ones is in the Chesapeake Bay even though it has been widely bred in captivity and is slightly popular among aquarists.


As one of those egg-laying tooth carps, Striped share similar characteristics with them.They have silvery appearance occupying the sand flats and tidal creeks area.

You can identify females to have three horizontal stripes on both sides while the males have up to twenty vertical bars on both sides of their bodies.

When it comes to base color and shape, both male and female striped killifish are generally uniform.

You can expect them to have silvery-olive coloration and a slender body that houses long-pointed snouts. Aquarists can simply use the bar appearance to differentiate male and female striped killifish.

The egg-laying nature of these is somehow different from other fish species.

It’s also interesting to know the fact that these, in general, can exist and evolve in such a warm environment.

They have different reproduction systems than their relatives we’ve mentioned previously.

Natural Habitat

Striped Killifish typically live in the swampy area with a water environment and trees that explain how they’re largely found in the Chesapeake Bay. They can either live in swamps, pools, or streams.

While it may vary for where they’re found, there is a specific natural environment to live well.

They prefer subdued lighting with a water temperature of 20-23C. The floating plants, whenever available, would be the main target for the females to lay eggs when spawning that can be replicated in captivity.

These inhabit the shallow streams and cooler temperatures whenever possible.

These also explain how striped killifish become the bottom dweller even though they may lay the eggs in the floating plants you’ve set up in the aquarium.

It is a peaceful species just like other killifish that can get along with its relative species in a community tank. However, replicating the shallow, slow-moving, and shady natural environment is very important if you want to keep them in your tank.

In general, they require generic considerations when they’re kept in captivity. However, you’d need to carefully choose the tank mates and decoration items.

Avoid hazardous installation when growing and keeping striped killifish in the aquarium environment.

For example, you should avoid the coarse, sharped edged gravel or substrates for the tank. Since they’re the bottom dwellers, they may scratch themselves with those materials. You need to use fine sands or substrates in the tank for sure.

Striped Killifish Care & Tank Setup

When kept in captivity, these should be introduced to aquarium environments that replicate and preserve their natural environment as much as possible.

Since Striped killifish is considerably less popular than other killifish, you may find limited information but here you can follow our general guide below.

It should be noted that these could have been captive-bred specimens that may be more adaptable to a wider range of water conditions. Still, we can work on the ideal water parameters to help them thrive in the tank environment well and have a longer lifespan.

These can thrive in general freshwater conditions but they could be sensitive to extreme water changes. You can maintain a pH value of 6.0 to 7.0 and the water temperature within the range of 68° and 75°.

Keep the water hardness in the range of 120 ppm to 160 ppm for the best possible water condition in the tank with striped killifish.

At this point, a reliable thermostat-equipped feature would be an essential investment.

With this tool, you can keep the proper temperature in the tank throughout time. Robust filtration is also crucial but it must be followed by partial water changes that you should do per week(10%) or two weeks(25%).

Make use of a siphon vacuum gravel cleaner or aquarium water changer to improve the water quality of the tank.

A water conditioner would be a great boost to ensure your tap water source is eligible for a freshwater environment. With proper water conditions, you can maintain the well-being and allow them to live longer.

They are small fish species that can live well in 5-gallon or 10-gallon species tanks if you keep a small group.

However, you may need a 20-gallon or larger tank if it’s for a community tank or if you want to keep larger groups. The setup would be different for striped killifish species and community tanks.

The decoration can involve Java moss, fern, cryptocoryne, driftwood, and plants. Floating plants would be necessary as well as the tight-fitting lid because striped killifish could be a great jumper. Keep the subdued lighting environment so they won’t be stressed out.

It’s better to use low-powered filtration to keep air and water shallow just like their natural environment.

Sponge filters or HOB are advisable to create the ideal water and airflow for them. On the other hand, you can support this environment with long rectangular fish tanks whether you’re using a 10-gallon or 20-gallon.

A larger tank is recommended as you need to provide more space for male’s territory. This way, you can prevent them from quarreling with each other in the species and community tank. If this is your first time to keep striped killifish, you better invest in a larger tank.

Tank Mates

Like most killifish, striped killifish is fairly peaceful when kept in species and community tanks. However, male killifish can be territorial towards its kind for some reasons. Generally speaking, setting up a community aquarium would involve more factors to consider.

Even though these can potentially live peacefully in the community tank, species selection should be your concern. Consult experts nearby or in online forums for insights. Always do thorough research before adding other species into the community tank with these in it.

If you want to set a community tank for your striped killifish, these are some species you may want to consider:

  • Dwarf Cichlids
  • Rasboras
  • Corydoras
  • Tetras
  • Small Loricariids

Still, you need to avoid larger and/or aggressive species to live together with them in the community tank. Boisterous fish are also ones you better avoid adding to the tank.

Food & Diet

Striped killifish is a carnivore species and they share the same diet as other killifish. You can find them accepting baby brine shrimp nauplii, mysis shrimp, daphnia, bloodworms, and mosquito larvae. However, they’d likely reject your dry food offers but can give them a shot because there are also success stories.

You can also use flakes and treats to feed these and see whether or not they accept your offers. Generally speaking, you better feed them with varied foods like previously mentioned. Ensure they have good quality and the proper size so your fish easily consumes them.

The ideal frequency of feeding is twice a day and you should never overfeed them. The feeding time shouldn’t be more than two minutes per session. Please immediately stop feeding if they’ve stopped eating because uneaten foods can contaminate and reduce the water quality in the tank.

Breeding Guidelines

Breeding striped killifish is somewhere between easy to difficult but you can use this general guideline. First of all, you’d need to use a separate breeding tank to breed them in captivity. Forget about attempting them in the species or community tank.

Again, the natural environmental approach is the winner if you want to have the fry from your striped killifish in the tank. The breeding tank would be better to have warmer water that eases and speeds up the hatching.

In the breeding tank, females would lay their eggs so the male can fertilize them. They may bury their eggs in the substrate as a form of depositing. Once the spawning has been successful, the eggs hatch within 12 – 41 days depending on the water conditions and other seasons.

Since striped killifish can spawn multiple times per year once they reach two years old and become mature. This way, you can expect more fry in your tank but you should also be ready with the spawning procedure.