There are approximately 1,270 species of killifish and all of them are just a little different from each other. Killifish are known for their amazing jumping ability. Killifish can be a great addition to your tank and they will brighten up the color of your community.
I talked to a fish expert at “Pets and Such” in Salt Lake City, Utah and he told me that a majority of Killifish are very passive fish and they can be tankmates with most other community fish.
Here is a list of 19 that would be good companions for your Killifish.
1. Celestial Pearl Danios
The Celestial Pearl Danios, also known as the “Galaxy Rasbora”, would be a great option to add to your aquarium if you want to add just a little bit of color. Celestial Pearl Danios do best with fish that are around their same size making them a good match to put in with your Killifish. They are generally not very aggressive so it would help to put them in with a fish like a Killifish. (source)
2. Zebra Danios
Zebra Danios are very active fish and they often need to be placed with other fish to feel at home. Even though they are very active they tend not to be very aggressive, which makes them a great match with Killifish. Zebra Danios struggle with larger fish but because Killifish are around the same size, this should not be an issue. Sometimes Zebra Danios can be hyperactive, which can be a struggle for other species, however, with the Killifish this should not be an issue considering their passive nature. (source)
3. Asian Stone Catfish
Asian Stone Catfish and other types of smaller catfish would be a great fit with your Killifish and may add some variety to the type of fish in your tank. Asian Stone Catfish are bottom-dwelling species and are very passive as well. This makes them a perfect match for Killifish who tend to move around. Asian Stone Catfish are very peaceful creatures used to living in peaceful streams, making them a perfect match for your Killifish. (source)
4. Rummy Nose Tetras
Rummynose Tetras are another community fish much like the Killifish. They tend to be found in groups more often than not so they are used to having company. One thing to keep in mind if you want to get some Rummynose Tetras to add to your tank is that they can be very sensitive to the temperature and quality of your water.
This makes them a really good match for the Killifish because Killifish are pretty durable and can survive in most water conditions. You can focus on allowing your Rummynose Tetras to be comfortable and your Killifish should be just fine. Rummynose Tetras are also very cheap and they are very popular. You should not have a problem finding them at your local pet store. (source)
5. Rosy Tetras
Much like the Rummynose Tetras, Rosy Tetras are a great addition to your community aquarium. Many people love the Rosy Tetras for their attractiveness and cheerful nature. Rosy Tetras tend not to be very aggressive and they like to be in smaller groups. Rosy Tetra is a perfect fit to be a tankmate for your Killifish. Rosy Tetras like similar water conditions to the Killifish and they tend to stick to darker more hidden areas away from other fish. (source)
6. Cardinal Tetras
The Cardinal Tetra is going to be one of the prettiest fish in your entire tank. It is also known for being one of the most peaceful types of Tetra. Cardinal Tetras would be a great match for your community and especially for Killifish. Cardinal Tetras can sometimes be a very hyperactive species, which tends to bother more shy fish, but with the Killifish this shouldn’t be a problem.
Cardinal Tetras likes to swim in the middle and top of your tank which is also where your Killifish will generally swim, so you want to make sure to have a big enough tank for them to both have space. (source)
7. Yellow Dwarf Cichlid
Yellow Dwarf Cichlids can adapt very quickly to most environments that you stick them in. A common problem that you will find with some fish is that they all have different requirements for water conditions and temperature.
Fish like the Yellow Dwarf Cichlids and Killifish are perfect for a community because they don’t have very rigid requirements when it comes to either of those things. Having Yellow Dwarf Cichlid in your tank is not only a good match for your Killifish, but they will match with lots of variety of fish in your tank.
8. Cockatoo Dwarf Cichlid
Cockatoo Dwarf Cichlids are known to be one of the easier species of fish to take care of. If you are still new to the fish game, these might be the perfect fish to match up with your Killifish. Just like some other types of Cichlids they do well in most water conditions and temperatures. Besides being easy to take care of Cockatoo Dwarf Cichlid are some of the prettiest fish that you will find in someone’s tank. They bring quite the pop of color to any community of fish.
9. Agassiz’s Dwarf Cichlid
This is a type of fish that can be a good fit for your Killifish; however, it is super important to make sure that your tank size is sufficient if you plan on investing in an Agassiz Dwarf Cichlid. They can be a little aggressive and territorial at times, but with their durability and flexibility in water conditions, they can be a pretty good fit for most types of fish. These fish tend to be a little bit bigger than your normal Cichlid so space is key when considering these as your Killifish tankmate. (source)
10. Blackline Rasbora
Blackline Rasbora is a very popular fish that has great durability. They have often been found in polluted water sources, so their transition into your aquarium should not be too difficult. They tend to be peaceful fish and they are carnivores which means that they eat a similar diet to Killifish. Having Blackline Rasbora in your tank will allow you to focus on more “needy” fish. They like to be kept in groups of 8 or more.
11. Brilliant Rasbora
Brilliant Rasbora is not very common in the aquarium business; however, they are a great fit to stick with your Killifish. Much like other Rasbora they are carnivorous and can adapt to many different types of water conditions. The Brilliant Rasbora are among some of the biggest Rasbora and you will want to make sure you have plenty of space before you place them in your community with Killifish.
Brilliant Rasbora are not found in very many aquariums however, the conditions they live in are manageable for anyone who is willing to take care of them.
12. Harlequin Rasbora
Harlequin Rasbora is another type of fish in the Rasbora family that would be a great fit for your Killifish. Harlequin tend to be a lot smaller than other fish and are extremely passive. Although they tend to swim in the middle and top of the tank, you may want to have some plants at the bottom of your tank for them to hide. These fish don’t respond well to aggressiveness at all. This makes them a pretty good fish for most Killifish considering they are also a more passive type of fish. (source)
13. Honey Gourami
Adding Honey Gourami fish to your tank will feel just a bit like adding a splash of sunshine. These colorful and vibrant fish are a great addition to any community tank and would be a very good match for your Killifish. Honey Gourami are very hardy and they tend not to be very aggressive with other types of fish. They are known to be very playful and cheerful, and if kept in a big enough tank they can be a great fit.
14. White Cloud Mountain Minnow
White Cloud Mountain Minnow needs to be in the presence of other fish and work great in communities of fish. They are not very aggressive making them a great tank mate for you Killifish. White Cloud Mountain Minnow like big groups but it is important for them to have a group of their own species, otherwise, they will withdraw and may face issues. They also require a little bit colder tank temperature, which fits with Killifish who can easily adapt to different conditions.
15. Rubber Lip Pleco
A Rubber Lip Pleco will make a perfect tank mate for almost any type of fish. They tend to stick to the bottom which makes them specifically compatible with Killifish who swim in the middle or top of your tank. They like to hide and don’t pay much attention to tank mates around them. You would want to make sure to give them plenty of space and hiding spots. In their natural habitat, their water conditions change often making them more resilient to changes in tank conditions.
16. Bristle Nose Pleco
The Bristle Nose Pleco is known for its bristles that sit around its mouth, giving them a unique look. Although these may look like scary fish, they are actually very passive and generally keep to themselves. Just like other Pleco they generally stick to the bottom of your tank, but you may occasionally see them climbing up the side of your tank eating algae.
This is a smaller type of Pleco and may be a better option for you depending on the size of your tank. Bristle Nose Pleco is a great fit for Killifish as they are flexible with water conditions and they stick to themselves.
17. Dwarf Pencilfish
Dwarf Pencilfish are generally an extremely shy type of fish and they can be a good fit with some types of Killifish. Dwarf Pencilfish work well with a community of fish that is mellow and not aggressive. Make sure if you put any Dwarf Pencilfish in your tank that you also have plenty of items in there for them to hide in. If they are placed in a tank with aggressive fish of any kind, you will probably not see them very often as they will hide for a majority of the time. (source)
Another expert from Everything Aquatic shared with me some more species that would fit well with Killifish and among that list was Guppies. Guppies are some of the most popular fish in the world and are great for beginners. They are very active fish as they move a lot, but they tend not to be aggressive towards other types of fish. They love to be in groups where they can be constantly moving.
There are many different colors of Guppies and because of their popularity around the world, they can be found for a fairly good price. They tend to breed easily, however, so that may be important to consider before you place too many males and females in a tank with each other. They would make a great fit for your Killifish as they are non-aggressive and they won’t really fight for the same food source. (source)
19. Ghost Knife
Another fish on the list given to me was the Ghost Knifefish. These fish do not look or act like other types of fish as they do not have fins, scales, or a normal tail. They are definitely unique-looking fish, but they would be a pretty good fit for a tank including Killifish.
Ghost Knifefish tend to be a little bit aggressive, especially if not kept in a tank that is big enough to allow them to move around at ease. They tend to rest during the day and come out at night to swim around. Ghost Knifefish are also carnivores just like your Killifish which should make it easier to feed them.
Because Ghost Knifefish do not have scales, they are very sensitive to bad water conditions. They must be kept in a tank that fits their specifications. This makes them a great match for Killifish as they can pretty much survive in any water condition.