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What Are Endlers?

Marty has been a tropical fish hobbyist most of his life. He has kept Endlers since February of 2013.

Lime Green Endlers from the Cumana region of Venezuela. There are various types of endlers.

Lime Green Endlers from the Cumana region of Venezuela. There are various types of endlers.

What Are Endlers?

Endlers (Poecilia wingei) are small, colorful livebearer tropical fish that originate from Venezuela. Endlers are relatively new to the tropical fish hobby with most strains introduced after 2006.

Where Do Endlers Come From?

Endlers were first discovered in Laguna de Patos in Venezuela by Franklyn F. Bond in 1937. These unique fish were pretty much forgotten about until they were rediscovered by Dr. John Endler in 1975 when he noted their beautiful metallic green coloration.

Most of the original 1975 Endlers were hybridized or lost their coloration over time and were all but lost to the hobby.

In recent years we have been fortunate that these beautiful tropical fish once again have been collected and distributed for all to enjoy.

Two Main Regions of Venezuela Where Endlers Are Collected

To date, Endlers have been discovered in two different regions in Venezuela:

  • Cumana region
  • Campoma region

Cumana Endlers

Many of the Cumana Endlers that have been introduced into the hobby in the United States were collected in Laguna de Patos and the surrounding area by Armando Pau and line bred and introduced into the hobby by Adrian Hernandez (AdrianHD).

Campoma Endlers

Most of the Campoma Endlers found in the hobby today were originally collected and distributed into the hobby by Phil Voisin (Philderodez) of the Netherlands.

Blue Star Endlers are a very popular Campoma Endler strain.

Blue Star Endlers are a very popular Campoma Endler strain.

The Joy of Keeping Endlers

Endlers are a pure joy to watch in an aquarium. Most strains have very bright vibrant coloration and beautiful patterns. Endlers occupy the entire space in an aquarium looking for food and courting. They will usually swim up to the side of the tank when they see a person walk by in anticipation of getting fed.

Caring for Endler Fish

Endlers are very easy to care for.

  • They enjoy a wide variety of foods but can be maintained on finely crushed high-quality fish flake food.
  • They enjoy aquariums with lots of live plants and good lighting.
  • Just about any filtration method can be used as long as the filter doesn't suck up the fish or their fry (baby fish).
Crushed flake food.  A favorite of Endlers and their fry.

Crushed flake food. A favorite of Endlers and their fry.

Breeding Endlers

Breeding Endlers is very easy. Simply put males and females together and wait for the baby fish to be born.

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Endlers produce live young or fry. Fish that produce live fry instead of eggs are known as livebearers. These baby fish can produce fry of their own within just a few months.

Breeding Success Can Lead to Failure

Because Endlers can produce so many young so quickly, it's possible to overwhelm the aquarium with an excessive bioload.

If the aquarium is overwhelmed by a large number of fish, it can quickly lead to illness due to the increased amounts of toxins in the water.

The two most common illnesses that can occur in an overcrowded aquarium is ich (Ichthyophthirius multifiliis) and wasting-away disease.

An Endler colony population can grow very quickly.

An Endler colony population can grow very quickly.

Ich (Ichthyophthirius multifiliis)

Ich is an external parasite that attaches itself to the body of the fish. When a fish is infected with Ich it can look like the fish has salt on its body.

If a fish is seen with the symptoms of Ich, the entire tank should be treated. Successful treatment may be accomplished with the addition of salt and increased water temperature.

Extreme cases may require medications that are specifically created to treat Ich. Some medications may be harsh and create other problems such as infertility in some fish.

Always read and follow the directions included with your fish medication. Care should be used in selecting medications to treat your Endlers.

A fish with the parasite Ich (Ichthyophthirius multifiliis).

A fish with the parasite Ich (Ichthyophthirius multifiliis).

Wasting-Away Disease

Wasting away disease may be caused by a number of factors, illnesses, or parasites.

As the name implies the fish slowly wastes away, becoming thin and malnourished.

Because wasting-away disease could be caused by a number of factors or illnesses, it may be more difficult to treat than some other illnesses.

Successful treatment may be accomplished by using salt or by using a combination of medications or an all-in-one treatment.

A female Endler showing signs of wasting away disease.

A female Endler showing signs of wasting away disease.

Weakened Endlers

Once Endlers have had to endure illness such as Ich or wasting-away disease, they can leave the colony in a weakened state, making them more susceptible to illness at a later date.

Your Endlers should be carefully observed for a few months to make sure there is no reoccurrence of the illness.

Endlers May Be at Risk of Extinction

There is some concern over their native habitat in Venezuela where they come from. Reports from those who have visited the waters from which they came from report habitat loss due to pollution and predation. This may be further complicated due to the political climate in Venezuela at this time.

Although there are new phenotypes being discovered, there is some concern that their habitat is being destroyed, putting the wild Endler population at risk of extinction.

The Risk of Losing Pure Endlers Forever

There is a genuine possibility that pure Endlers could be lost to the hobby over time. The main reason for this is because Endlers can easily breed with guppies.

Like guppies, female Endlers can save the sperm from just one visit with a male guppy for a year or possibly longer. If a female Endler is ever exposed to a male guppy, it should no longer be considered for breeding pure Endlers.

Another problem is that female Endlers look nearly identical to female guppies.

Accidental Hybridization

Because Endlers breed so readily with guppies, accidental hybridization can occur even with the greatest of care.

Ideally, any breeder that wishes to keep and produce pure Endlers should not keep guppies in the same location.

Endlers and guppies can easily jump from one tank to another, giving them an opportunity to escape into another aquarium.

Even if the breeder sees the fish jump into another aquarium, if it was a female, it may be impossible to identify among the other female fish in the aquarium.

Yellow Tiger Endlers.  One of the first accidental hybrid Endlers ever produced.

Yellow Tiger Endlers. One of the first accidental hybrid Endlers ever produced.

Natural Hybrid Endlers

Not only is there a risk of accidental hybridization of Endlers kept in captivity, but Endlers have also been exposed to guppies in the wild.

Endlers seem to prefer their own species over guppies, however, when they are placed in a situation when there is a limited number of Endlers to breed with compared to guppies the Endlers will readily breed with guppies.

Male guppies have several hooks on their sexual organ, a modified fin called a gonopodium. These hooks force female guppies and Endlers to breed with them.

Male Endlers have one small hook on their gonopodium and primarily rely on courtship instead for forced sex.

Many of the Endlers that have been captured in the wild appear to be natural hybrids. There has been a longstanding dispute between Cumana region Endlers or Compoma region Endlers tend to be purer.

Red Chilli Endlers, a type of hybrid Endler being sold in a pet shop.

Red Chilli Endlers, a type of hybrid Endler being sold in a pet shop.

Is Breeding Hybrid Endlers a Bad Thing?

With pure Endlers being in such a risky position of being lost forever, is it wrong to keep or breed hybrid Endlers?

The answer really depends on who you ask. There have been many beautiful hybrid strains of Endlers that have been developed. Many of these hybrid Endlers are very popular and have contributed to Endler's popularity.

The important thing is that hybrid Endlers are clearly identified as hybrid Endlers so that hobbyists are not confused as to which Endlers are pure and which are hybrid.

Unfortunately, hybrid Endlers are rarely identified as hybrids when they are sold in pet shops. Those who desire to keep purebreds may wish to avoid purchasing their Endlers at pet shops as most pet shops don't have the ability to ensure that Endlers don't accidentally come in contact with any other livebearers.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2021 Marty Andersen

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