Because of their small size (even as adults) they make an excellent choice for small desktop aquariums, but do enjoy a roomy environment when available to them. Also, Endlers are an especially peaceful fish so get along extremely well with other peaceful fish in a community set up. See the Recommendations section below for a list of some common compatible fish and other tank inhabitants.
Endlers are tirelessly active, always swimming about their environment, pecking at algae, displaying to one another or generally investigating anything that catches their attention. They are also insatiably inquisitive and some of the most fearless freshwater tropical fish I've seen. They are only briefly phased by disruptions to their tank. Even while doing tank maintenance, they will often come to investigate and nibble at your fingers or get close to a siphon hose.
Although they appear to establish a pecking order, no real fights seem to occur other than some good-natured chasing. Adult males often "flare" or "display" at their reflection on the tank glass, to each other and, of course, for females. They are very mild-tempered and don't bother tank mates.
They freely use all parts of the aquarium, seemingly without preference, happy to check out whatever is in the vicinity. As their tank becomes dark, most Endlers will sink to the bottom and “sleep” there until the light returns. Occasionally Endlers choose to overnight near the top as well, which often happens in community tanks with larger fish that inhabit the bottom.
Males are noticeably smaller than females and are strikingly colorful, while females are larger and plumper and are relatively monochromatic in shades of silvery tan. Breeding will take place as long as there are males and females within the same tank and does not require any special preparation such as water parameters, depth, temperatures, male/female ratio, plants, substrate or altered light schedules that are required to breed many other fish species.
They give birth to live fully-formed young (fry) approximately every 23 days as their “livebearer” name suggests, rather than laying eggs. Female Endlers (and many other Poeciliid livebearers) can store sperm from prior matings, so may continue to produce fry for up to a year when males are not present (known as superfetation / superfoetation). Fry “drops” or “broods” can range in size from 1 to 30 fry depending on several variables, including female size and age. The fry, although small, are easy to see and are active swimmers soon after birth. Warmer water temperatures appear to favor male fry development, while cooler temperatures favor female fry development. An even ratio (50/50) seems to be produced at about 77° F (25° C ).
Although adult Endlers rarely eat their young, the fry can make a tasty snack for other tank mates. To help ensure survival, they should be kept in a tank with plenty of hiding areas or in a densely-planted tank. Alternately, raise the fry in a separate small tank until they are too big to be eaten. Endler fry will grow very quickly when fed a few times per day. Males attain breeding age and will produce adult color in 3-5 weeks but usually take a few months to develop full color depth & intensity. Females can usually produce small fry drops at about 8 weeks.
As a final note, Endlers will easily hybridize (crossbreed) with the common guppy, which results in fertile offspring. Since Endlers are thought to be extinct in their natural habitat, the subject of Endler hybrids can create heated arguments between hobbyists. Many enthusiasts believe Pure Strain Endlers should never be crossed with guppies to help ensure their unique combination of traits are preserved. While other hobbyists are interested in crossbreeding for specific traits or to discover new interesting combinations of traits. For more information on known species Endlers have hybridized with and additional genetics information, see the Genetics section of the Details page.
Endlers are omnivorous and will eat most of the commercially available fish foods providing the food will fit into their small mouths. Most flake food is too large and should be crushed into smaller sizes before feeding. A high-quality vegetable matter is a great staple, but a varied diet is always best. Endlers can also be fed frozen or live foods such as brine shrimp, grindal worms, blood worms, tubifex worms, brine shrimp, and other small invertebrates. Fry will eat finely crushed flake food or one of the specially-prepared micro/powder fry foods on the market. Both fry and adults will nibble on any algae they find in their tank. The Endler Shop has developed Endlers Special Blend Flake Food, designed as the perfect daily staple for Endlers. See the Order page for ingredient details and to order.
Endlers will quickly learn the schedule you use to feed them. When it’s feeding time, they will swarm in anticipation, darting to whatever part of tank is closest to you. They can also be trained by lightly tapping on the aquarium rim to alert them to the feast.
Population Control: Just a few females will very quickly produce more fish than most hobbyists can handle. Purchasing more males instead of females will initially help keep the number of births lower. Also, keep your tank temperatures at 78°F to 80°F as this should help produce more male fry.
Mixing Strains: Mixing males & females of different strains (like Black Bar & Peacock) in the same tank will produce offspring with traits of both strains. Use separate tanks for each strain to keep offspring traits pure. Use one tank for many strains if you want to mix those traits in subsequent generations.
Natural behavior: A group comprised of about 6-8 is sufficient for the Endlers to exhibit their “usual” and “natural” characteristics and behaviors.
Breeding colony: 8 to 10 Endlers is a good genetic base from which to start a breeding colony.
Tank size: The usual rule of thumb of having one gallon of water for each inch of fish in a freshwater tropical tank is sufficient. A higher density of fish is possible if the tank is heavily planted and/or if filtration capacity is ramped up.
Compatible tank mates: Endlers make a great addition to a community tank with other small peaceful fish, including, but not limited to, Cory Catfish, small peaceful Tetras (like Neon Tetras), White Clouds, Honey Gourami, Glass Fish, Ghost & Cherry Shrimp, Dwarf Corydoras, small Rainbowfish, Otocinclus Catfish, Zebra Danios, Bolivian Ram Cichlids and African Dwarf Frogs. Endlers are also great in a single-species tank because of their constant curiosity and endlessly active nature.
Water current: Endlers should not be subjected to strong water currents.
Increase pH & water hardness: Livebearers prefer higher PH & harder water. In fact, if you notice listlessness or disinterest in food, it's likely pH and water hardness (dissolved minerals) are too low. Strive to keep tank water in the “hard” range as per standard water parameters tests. A helpful remedy for low PH is to keep a small bag of crushed coral in the filter. Also, adding "wonder shells" to the tank helps maintain pH and adds essential dissolved minerals.
Salt: In their native Venezuelan coastal lagoons, Endlers were often exposed to salt water from the nearby sea, so evolved to tolerate and even thrive in salt water environments. In fact, there have been reports they can withstand salinity levels up to 150% of normal seawater. And they can breed in both fresh water and marine conditions. If you decide to add salt, a good baseline is 1 tablespoon per 5 US gallons. You should ensure other fish and plants in the tank can handle this as well.
Cover your tank: Endlers are good jumpers, so be sure to cover your tank to avoid any fatal escapes.