How many Endlers should be kept together?

Quick Summary

The recommended minimum number of Endlers to keep together is 5-6. Keeping Endlers in groups helps reduce stress, allows them to exhibit natural schooling behavior, and makes them less shy. While a pair or trio can work, larger groups are ideal. Aim for at least 5-6 Endlers, though tanks that are large enough can support more. Provide plenty of hiding spots and line of sight breaks to allow sub-groups to form.

How Many Endlers Do Well Together?

The ideal group size for Endlers is around 5-6 fish. This allows them to school comfortably and reduces stress compared to keeping just a pair or trio. With 5-6 Endlers, they will have companions to interact with but also enough space to avoid aggression.

Some aquarists have had success keeping pairs or trios of Endlers, but they tend to be shyer and more stressed than larger groups. Endlers are social fish that prefer to be kept in groups. Pairs and trios often hide more and can become territorial towards each other in smaller tanks.

Groups of 5-6 Endlers allow the fish to exhibit their natural schooling instinct. In a larger group, they will swim together, displaying their vibrant colors as they network. This is when Endlers are at their most active and vibrant.

The more Endlers you keep, the more impressive their schooling display will become. Groups of 8-10+ Endlers can work well in larger tanks. Make sure to provide plenty of plants, rocks, and other decor for them to interact with.

Here are some general Endler group size guidelines:

– Minimum: 5-6 Endlers
– Ideal: 8-10 Endlers
– Maximum: 10-12 Endlers in a heavily planted 29+ gallon tank

The actual maximum number that will work depends on tank size, tank mates, tank layout, and your Endlers’ temperaments. Monitor your group for signs of stress or aggression and be prepared to separate fish if needed. Providing lots of sight breaks can allow for larger group sizes.

Benefits of Keeping Endlers in Groups

Here are some of the biggest benefits of keeping Endlers in appropriately sized groups:

– Exhibits Natural Behavior: Endlers are schooling fish, so groups allow them to swim together and display normal schooling and shoaling behaviors. This stimulation is important for their health and reduces stress.

– Social Interaction: More Endlers allows for more fish-to-fish interaction. Endlers communicate with body language and need companionship. A larger group size provides engaging social opportunities.

– Reduced Aggression: Male Endlers can spar with each other, especially in pairs or trios. More Endlers spreads out aggression and provides target fish to redirect nipping behavior.

– Security in Numbers: Being part of a group provides security for each individual Endler. They can signal dangers to each other and feel safer with safety in numbers.

– Less Shy: Endlers tend to be shyer in smaller groups and may hide frequently. Larger groups bring out their confidence, activity levels, and colors.

– Impressive Display: A larger Endler school moving together through the tank is a spectacular sight! More Endlers allow for an impressive schooling display.

Keeping Endlers in an appropriate group size results in happier, healthier, and better behaving fish. Make sure to provide them with plenty of swimming space for their group and enough plants and decor for subgroups and territories to form.

Tank Size Considerations

Tank size must be taken into account when deciding how many Endlers will comfortably fit together. Here are some general tank size guidelines for Endler groups:

– 10 gallon tank: Minimum of 5 Endlers, with 8-10 being ideal. This size tank can support a larger group size if planted heavily.

– 20 gallon tank: Comfortably houses 10-12 Endlers, especially if aquascaped with lots of territory markers and sight breaks.

– 29+ gallon tank: Could potentially hold 12-15+ Endlers if the tank is decorated well to break up lines of sight and allow sub-groups to form. Monitor for signs of stress.

– 15+ gallon species only tank: Can hold a larger group of 12-15 Endlers without tank mates.

As always, observe your Endlers’ behavior regardless of tank size. Some groups will thrive at larger numbers than others based on individual temperament. Separate any fish that seem stressed or are bullied. Tank shape can also influence how many will fit – focus on swimming space rather than just tank volume.

Do not keep just 1-2 Endlers in most normal sized community tanks, as this is stressful. Ensure the tank size can comfortably fit a minimum group of 5-6 Endlers with room to swim. Bigger is generally better when it comes to Endler group sizes and tank sizes.

Influence of Tank Mates

The types of tank mates also influences ideal Endler group size. In general, the fewer tank mates, the more Endlers that can be kept.

Tanks with no other fish besides Endlers can comfortably house larger Endler groups. A species only tank allows for more Endlers, since they won’t compete with other fish and won’t have their schooling disrupted.

If keeping Endler’s livebearers with guppies or mollies, these similar fish will form a general school together. You can keep a slightly smaller group of 6-8 Endlers with other schooling fish. But don’t add too many tank mates, or the Endler school will be broken up.

Semi-aggressive fish like tiger barbs can nip at Endlers, meaning fewer Endlers should be kept in these tanks. Keep Endler groups at the smaller end of the recommended spectrum if their tank has aggressive fish.

Bottom dwellers like cory cats and plecos have minimal impact on how many Endlers will fit. They occupy a different tank zone. These types of tank mates allow for larger Endler group sizes.

Here are the tank mate situations that allow for larger Endler group sizes:

– Species only Endler tank
– Schooling fish tank mates (small groups of similar species)
– Bottom dweller tank mates

Tank mate choices that warrant smaller Endler groups include:
– Large or aggressive fish
– Messy fish that increase bioload
– Nippy fish (barbs, gouramis)
– Larger schooling fish that disrupt Endler schooling

Get to know your tank mates’ temperaments and behaviors when choosing your Endler group size. Prioritize giving the Endlers enough swimming space and schooling opportunities.

Importance of Tank Setup & Decor

How you setup and decorate the Endlers’ tank is just as important as size when determining ideal group size. Providing a complex environment allows for larger group sizes.

Here are some tank decorating tips:

– Use plenty of live or silk plants to break up lines of sight between males. Floating plants are ideal for shelter and to diffuse aggression.

– Include rock caves, driftwood, and other structures that create a sense of territory and visual barriers.

– Arrange decor to form several distinct territories and small areas within the tank. This allows sub-groups to form.

– Use tall plants like Vallisneria to give different schooling levels. Have some open schooling areas too.

– Introduce floating plants like hornwort or duckweed. These provide overhead cover and shelter for any fish being bullied.

– Place more decor and plants towards tank edges to utilize the entire tank footprint. Open middles can lead to aggression.

– Establish the tank well before adding Endlers. A mature tank with algae growth provides additional grazing and cover.

A natural looking aquascape goes a long way in increasing the number of Endlers that can coexist happily. Provide resting spots throughout the tank so no fish are forced to constantly swim and socialize.

Best Aquarium Plants for Endlers

Here are some of the best aquarium plants to provide shelter and enhance Endler colors:

– Hornwort: Floating plant that provides shelter and tannins
– Java Moss: Soft moss that diffuses aggression and gives hiding spots
– Anacharis: Fast growing stems for breaks in the water column
– Water Wisteria: Short bushy leaves that break up lines of sight
– Floating Plants: Frogbit, duckweed, etc for overhead cover
– Amazon Sword: Tall leaves with peaceful resting spots

Aim for a heavily planted tank with plenty of driftwood, rock caves, and other tank decor. This allows for the largest Endler group sizes by providing shelter and reducing aggression between males.

Signs of Stress in Endlers

When keeping Endlers in groups, monitor their behavior for any signs of stress or aggression:

– Hiding: Fish that stay hidden in plants and decor, especially if darker colored.

– Bottom Sitting: Fish that hang out at the bottom away from the group could be bullied.

– Skittish: Endlers that are jumpy when you approach or dash away may be stressed.

– Fin Nipping: Ripped fins are a sign males are sparring too aggressively. Separate any victims.

– Rapid Breathing: Watch for Endlers breathing rapidly even when not swimming quickly.

– Clashing: Males chasing, nipping, or ramming each other excessively.

– Flared Gills: Frequently see gills flaring as a sign of feeling threatened.

– Color Loss: Stressed fish will fade in vibrance. Healthy Endlers should be brightly colored.

– Loss of Appetite: Check that all Endlers are eating during feedings and not hiding.

Immediately remove any Endlers showing signs of chronic stress or illness. Consider separating very dominant males or bullies as well. Adding more plants and rearranging decor can also help reduce aggression.

Optimizing water quality helps keep Endlers healthy and reduces stress. Perform regular partial water changes and test ammonia, nitrite, nitrate, pH, and temperature routinely. Reduce bioload or use live plants to absorb excess nitrates if levels creep up. A well-maintained, stable aquarium supports larger group sizes.

Gender Ratio Considerations

The male to female ratio influences Endler group dynamics. Males are more aggressive and active compared to females. Having too many males causes excessive sparring and stress.

Some general Endler gender ratio guidelines include:

– 2-3 Females per Male: Best ratio for reducing male harassment while still allowing breeding. A 10 gallon could do 3 males, 9 females.

– 1 Male per 2-3 Females: An even safer ratio for less aggressive males. Helps shy males breed.

– All Male Groups: Can work in a heavily planted tank with 5-6 males. Requires lots of breaks in line of sight.

– 1 Male Endler Harems: A single male with 4-6 females limits male rivalry.

Monitor males when keeping multiple together. Remove excess males or victims of harassment. Introduce extra tank decor and plants to decrease male visibility before removing fish if possible.

Adding additional females splits male attention, reducing aggression directed at any single female. Have backup tanks or plans to deal with offspring and strain if breeding heavily.

Culling Excess Males

Since Endler’s livebearers readily breed, you may need to cull excess males to maintain ideal group numbers and gender ratios. Some options include:

– Pet Store Donations: Many local fish stores will accept extra healthy Endlers as donations. Call ahead to ask.

– Aquarium Clubs: Find a local aquarium society and offer excess Endlers to club members.

– Aquarium Classrooms: Donate extra Endlers to school classrooms looking for fish. Good learning opportunity.

– Online Giveaways: Use aquarium forums, Craigslist, Kijiji, Facebook groups, etc to find new homes for Endlers. Many hobbyists will take free fish.

– Control Breeding: Use all-male groups, artificial plants, cooler water, or other methods to slow breeding and fry survival.

– Leave Fry for Natural Culling: Let adults eat some of their young to reduce numbers. Nature’s way of stabilizing populations.

– Culling: As a last resort, humanely euthanize excess Endlers using clove oil or other proper fish euthanasia methods.

Avoid releasing Endlers into outdoor ponds and waterways, as this can introduce invasive species or diseases. Try the other options first before resorting to culling. Maintaining stable male to female ratios through selective removal helps provide ideal breeding and group dynamics.


The ideal Endler group size is around 5-10 individuals, with 5-6 being a good starting point. This allows them to display natural schooling behavior without too much male aggression. Heavily planted tanks can support larger group sizes of 12-15 Endlers, especially in species only setups.

Monitor Endlers for signs of stress like hiding, skittishness, and frayed fins. Remove any harassed fish. Adding more females helps limit male aggression too. Maintain at least a 2:1 female to male ratio, or even 3:1 in community tanks.

Cull excess males through ethical methods like donations, giveaways, or selective breeding management. Properly aquascaping the tank provides sight breaks and territory markers that support larger group sizes. Focus on giving Endlers adequate swimming space and opportunities to exhibit schooling behavior when determining ideal group sizes.

Leave a Comment