Killifish Tank Setup Care Guide

If we go by their name, you’d think Killifish are scary predators. But they’re actually gorgeous and far from being scary-looking.

Their name actually refers to their reproductive strategy and was derived from the Dutch word “kill,” meaning “small stream,” where killifish spawn.

Killifish are small but hardy aquarium inhabitants, typically living 2-3 years (some species can live up to 5 years) and ranging from 1 to 6 inches in length. There are many species of killifish. Some of the more popular ones we carry are:

• Blue Lyretail Killifish
• Clown Killifish
• Norman's Lampeye Killifish

Their vibrant colors and intricate patterns never fail to catch the eye. They are mostly peaceful, except for some males who can be a bit territorial. They’re also excellent jumpers, so make sure your tank is covered.

What truly sets Killifish apart is their breeding behavior. Many are annual spawners, laying eggs that can survive dry periods. 

Setting Up Your Killifish Tank

Here are a few elements to consider when setting up a killifish tank:

Tank Size & Selection

A 10-gallon tank works well for a small group of about 3-5 killifish. If you're planning a community tank, go for 20 gallons or more. A 20-gallon tank can house up to 8-10 killifish, depending on the species.

For those with limited space, desktop tanks are great options for nano killifish species. These smaller setups, around 5 gallons, can be perfect for a pair of tiny species like Cape Lopez lyretail (Aphyosemion australe) or the Clown Killifish (Epiplatys annulatus).

When stocking your tank, maintaining the right male-to-female ratio is crucial for harmony. I recommend a ratio of one male to two or three females.

This ratio reduces male aggression and stress for females. In smaller tanks, consider keeping just one male with several females.

It's always better to err on the side of less crowded. Your fish will be healthier and show better colors with more space. 

Filtration

Most Killifish prefer calm waters, so gentle filtration is key. I always recommend sponge filters for killifish tanks. They provide excellent biological filtration without creating strong currents that could stress your fish. They're also safe for fry if you're breeding.

Substrate & Decorations

For substrate, fine sand or small gravel is recommended. Both work well, but gravel can be easier to clean. 

Remember to add hiding spots. Driftwood and small caves make your fish feel secure and provide interesting focal points in your tank.

Lighting

Killifish thrive in subdued lighting conditions. Low-intensity LED lights provide enough light for plants while keeping the environment calm for the fish. Additionally, they're energy-efficient and don't heat the water like some older lighting options.

Creating the Ideal Killifish Habitat

Let's look at the most important aspects of their habitat:

Water Parameters 

Killifish thrive in slightly acidic to neutral water. A pH between 6.0 and 7.5 is recommended. Don't forget to use a good dechlorinator when setting up your tank or doing water changes.

A weekly 20% water change to keep everything pristine is recommended.

Temperature Control

 These fish prefer cooler room temps, around 68-79°F. 

A cool thing about Killifish is that many species don't need heaters. They're happy in room-temperature water, without heating equipment. Just make sure your room doesn't get too cold at night.

Live Plants

Live plants in Killifish tanks are recommended. They help maintain water quality by absorbing nitrates. Plus, Killifish loves darting in and out of plants.

Some species, like the Blue Lyretail (Fundulopanchax gardneri), lay their eggs on plant leaves. This species is also somewhat territorial, and taller live plants such as Swords, stems, and ferns will help break up sightlines and create little microterritories they'll feel safe in.

This 'Trident' Java fern is a great go-to choice. They're hardy and don't need much light.

Keeping Your Killifish Thriving

Once you've set up the perfect home for your Killifish, it's time to focus on their ongoing care. Here's how to keep them happy and healthy:

Feeding

Killifish are protein lovers; they’ll snack on a mix of live and frozen foods. Brine shrimp and bloodworms are top choices. Species like the Golden Wonder Killifish (Aplocheilus lineatus) go crazy for mosquito larvae.

For variety, toss in some high-quality flakes or pellets a few times a week.

Maintaining Water Quality

Clean water is crucial. About 20% of water change every week without fail will keep the water clean. However, the frequency may vary according to stocking density, filtration, plant load, and feeding habits.

Observe your tank and adjust the schedule accordingly. A gravel vacuum to remove debris helps a lot, too. 

Disease Prevention

Honestly, the best way to prevent diseases is to keep that water clean.

You’ll rarely have health issues with your killifish with regular maintenance. If you're curious about specific fish diseases, read this blog.