(Article initially written for the Silicon Valley Aquarium Society newsletter, as a "species journal" article.)

While doing some research while seriously getting back into fish keeping for the first time in some years, I realized I kept coming across one totally new fish again and again—the Endler’s Livebearer. Most of the information I stumbled across was on the “Are they a guppy or are they not?” debate. (This was before the Endler’s was officially classified as Poecilia wingii in spring of 2006). This aroused my curiosity, so of course I HAD to have some.

I found male “Endler’s” at a couple local fish stores, but ran into two problems—first, a complete absence of female Endler’s, and second, the fact that the available “Endler’s” really looked like Endler x guppy hybrids, with lyre tails, extended swords, and snakeskin patterning I was sure I’d never seen in any quality information page on the fish. (I later learned this was an issue with the suppliers, not the stores themselves.) So eventually I turned to EBay and Aquabid, and won an auction on a pure breeding pair with 4 unsexed, but mostly grown, fry of theirs.

My first sign that these fish were not guppies was when they arrived in the mail, well packed in a big Kordon breather bag, and I realized that not only were there 6 near-adult fish, there were ten newborn fry in the bag, alive and healthy. Cannibalism was one of the factors that most turned me off to “traditional” livebearers in general and guppies in particular, so I was shocked and thrilled to find the little ones unharmed.

The whole lot went into a Marineland Eclipse 12 gallon that had been set up as a species tank for them, and they settled in happily and quickly. The mature female did not drop fry the next month, which I’m attributing to stress, but in the meantime the juveniles quickly, grew and differentiated into young adults. They turned out to be 2 males and 2 females, and the next month all 3 females dropped fry—the large original had over a dozen, the younger two dropped 2 and 3 respectively. They’ve been breeding reliably since then, and the “special delivery” fry became sexable as well at between 2 and 3 months, although they have not yet started to breed.

Endlers are very easy keepers. Really, just keep them wet. They'll take any sort of food, including flakes. They are not at all fussy about their pH, and can tolerate a range from 6.0-8.0, although there is no reason to not just keep them near neutral. Water temperature is equally forgiving. Their ideal range is the normal tropical aquarium range, 74 to 78 F, but can tolerate water into the high 60's to the high 80's.

They are extremely hardy little fish. I’ve had a fry loss here and there, but have not had a single Endler’s die after a week of age, and I’ve had the colony for nearly 6 months. They were the only species in my fish room to survive a 2-week long heat wave (in the 100’s, without AC) with no losses. Extreme sensitivity to water fluctuations and high loss rates caused great frustration with fancy guppies, and are major reasons why I have not kept them for many years.

The basic color pattern for a male Endler’s starts with a big black “comma” running from his dorsal fin to his gills. (The comma is the first marking to appear, and the first sexual distinction—it shows even before the gonopodium is visible). The tail is mostly clear, with a bright metallic orange streak on each edge. Typically, the bottom streak runs the full length of the tail while the upper streak is roughly half that long. The body then has mottled patches of the same metallic orange and an equally metallic lime green. A metallic baby blue occasionally shows up, sometimes on the body, often on the dorsal fin. The females, when young, resemble female wild guppies, but become a bit more distinct as they age. Once they reach about one and a half times the size of the male, their plain silver/gray color begins to take on a very pretty bronze or gold hue. Their scales pick up more pigment on the edges, giving them a clear “fishnet” or pineapple pattern as the body color deepens. Occasionally, the females will pick up a nearly transparent blue shimmer on the dorsal or anal fins. Although the females are plain by many people’s standards, and somewhat of late bloomers, to me they are very simple but quite elegant fish when they mature.

Endler behavior patterns are distinct from the guppy, as well, particularly regarding their courtship. Male guppies are notorious for attempting to sneak up on and mate with anything that moves, and some things that don’t, and have been known to gang up on and harry females to exhaustion and death. Endler’s don’t partake of this same behavior. They’re not “sneaky” about trying to get a poke in anywhere they can—they actually court their females and almost remind me of little bettas. They hover in front of the female they’re trying to impress, flutter their fins, show off their colors, and display like tiny swimming peacocks. If the female seems uninterested, they may try to step up the show, but if she swims off, they’re not prone to sneaking up behind her and trying to mate anyway.

Endler’s are a fantastic little livebearer for someone looking for something a bit different, and in fact rekindled my interest in livebearers for the first time in a decade, and led me to recently begin working with Heterandria formosa (“least killifish”), halfbeaks, and goodeids as well. They make a wonderful, colorful display for a small tank and I feel they deserve a place equally in a small casual office desk tank or in the breeding rooms of a dedicated hobbyist.

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