An Endler group is never really a fixed number, and that is the first thing to understand before you buy any. Six is a sensible starting group, but a mixed-sex colony of six becomes twenty surprisingly quickly, because females can produce fry every few weeks and young mature fast in warm water. So the honest answer has two parts: stock at least six for social comfort, and decide before they arrive whether you actually want a breeding colony or a display group of males only.
Why Endlers Need Company and Female-Heavy Ratios
Endler's livebearers are busy, social fish that graze, court, and explore in loose company all day. A lone male or a single pair lives under constant strain, because the male directs all of his persistent courtship at one female, who then hides, skips food, and wears out. Two or three females per male spreads that attention across the group. In a starting group of eight, three males and five females is a workable balance. The males still display their orange, black, and metallic markings constantly, but no single female is followed from morning to night.
The All-Male Option for Small Tanks
If your tank is small or you simply do not want fry, an all-male group of six to eight Endlers is a genuinely good setup rather than a compromise. Males are smaller and far more colourful than females, they spar harmlessly in brief chases, and without females present the group stays exactly the size you stocked. Provide planted cover and visual breaks so a chased male can step out of sight, and feed a varied small-particle diet. What you must not do is add one or two females later on a whim, because that single change restarts breeding and the population planning that comes with it.
Planning for Fry Before They Arrive
A breeding group needs an exit plan for young fish. Some fry will be eaten, but in a planted tank many survive, and within a few months the group can outgrow the filter and the water-change routine that kept it healthy. Decide early whether fry will be moved to a grow-out tank, passed to other keepers, or separated by sex once young males show colour. Dense floating plants give fry their best survival chance if raising them is the goal. Watch the adult count at feeding time each week, since gradual crowding shows up first as slower growth and more waste between water changes.
Keeping the Colony Counted and Cared For
Because this group's size changes without anyone buying a fish, routine counting is real care, not bookkeeping fuss. Note births, removals, and deaths, keep up water changes sized to the actual population rather than the original six, and thin the group before water quality slips instead of after. A colony that stays counted stays healthy, and rehoming surplus males early is far kinder than letting numbers quietly double.
That counting habit is easier when it is assigned rather than assumed, and KinsLe Care Teams lets you hand the weekly Endler head count, fry check, and water-change duty to specific helpers, with each finished task marked by a timestamp.