The Fantail Darter: an Ideal Resident for the Riffle TankBy Cliff Zoller
reprinted from American Currents, Summer 1997
What it lacks in color, it more than makes up for in personality. The fantail darter (Etheostoma flabellare) is a scrappy, territorial little fish that bravely defends its eggs against predators many times its size.
It's not that the fantail is unattractive; its colors are just a little subtle, that's all. The fantail has a background color of straw brown, overlaid with dark bars and/or longitudinal pin stripes, with the overall color darkening towards the head.
Breeding males are darker, with vivid banding in the tail fin, and an almost black head. The forward dorsal fin is very low and in the male is topped by bulbous growths on the tips of the spines. Presumably, these bulbs serve as egg mimics-- held against the roof of the spawning cave to convince potential mates that their owner is a male whom other females have found worthy of spawning with. This design, incidentally, is at its most extreme in the lolly-pop darter (Etheostoma neopterum), in which breeding males have egg mimic bulbs on both the forward and rear dorsal fins.
Females can be identified by their lighter color, lighter tail bars, lack of dorsal fin knobs, and, near the time of spawning, full abdomens.
During spawning or territorial defense, the breeding male's head turns black and a vertical black "flame" appears through the eye-- in stark contrast to the bright gold of the iris. Because of their upward turning mouths, fantail darters are often forced to run at their opponents at a tail-up, 45° angle.
The fantail spawns in spring, in moderately flowing riffles. Like the johnny darter (Etheostoma nigrum), fantails spawn upside down under a rock.
The male guards the nest until the eggs hatch. This may explain why, in the aquarium, fantails are much more hostile towards johnny darters than they are towards other gravel-nesting species.
To spawn the fantail in the aquarium, it's critical that the ceiling of the rockwork "cave" be just high enough for the female to rest upside down with her pelvic fins touching the ceiling. During spawning, the male and female fantail darter align head to tail. The female remains upside down for as long as an hour, during which time several egg-laying episodes occur.
Both the johnny darter and the fantail darter have benefited from their upside-down method of reproduction. Because their eggs are up off the bottom, they can flourish in areas where agriculture has caused increased siltation, which will often smother the eggs of gravel-spawning species.
To keep fantails in the community riffle tank, it's important to give them enough space-- a square of about 10 to 12 inches for each male. Be sure to provide artificial caves in the rockwork, so that the dominant males each have their own hideout and the others can find a place to escape. I've found I can keep five fantails in a 40-gallon long tank if I provide two caves at each end and a cave in the middle. Iıve also found that it's best to arrange the caves to block the fishıs views of each other. The least dominant fish will retire to the tops of the rocks, out of the line of sight of the dominant fish. The cave owners tend to remain in their lairs until feeding time.
Although they exploit many food sources, in the wild the fantail's diet consists largely of the nymphs that cling to the underside of rocks. In the aquarium, they seem to do very well on frozen brine shrimp (which I usually feed all my fish). I leave an open area in the center of the tank, into which I pour the shrimp, after having first turned the filter off. The fantails will squabble a bit as they get too close to each other, but all seem to get enough to eat.
Fantails are easy enough to collect: Check the range map in Petersen's Field Guide to Freshwater Fishes North of Mexico and find a riffle about 12 inches deep in a small, cool water stream. Then, place a flat headed dip net on the bottom, agitate the rocks just in front if it, and check the dip net periodically.
Becker, G. 1983. The Fishes of Wisconsin. University of Wisconsin Press, Madison. 1,052 pp.
Etnier, D. A. and W. C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press, Knoxville. 681 pp.
Page, L. M. 1983. Handbook of Darters. TFH Publications, Neptune City, N.J. 271 pp.
Used with permission. Article copyright retained by author.