Poecild's files
HETERANDRIA FORMOSA (Girard
1859)
Mosquito Fish, Dwarf Top-Minnow, Dwarf Livebearer, Least Killifish, Lesser Killifish, Pygmy Livebearer
Heterandria
formosa
an
extract from the article Three Unusual Livebearers by Howard Norfolk. Original publication :
Vancouver Aquatic Hobbyist Club Newsletter.
You can find the whole article here: http://www.aquarticles.com
H.
formosa
is not a killifish, but is in fact the smallest species of livebearer, and
for that matter one of the smallest fish species in the World, and until
recently was considered to be the smallest known vertebrate in the U.S.A.
The males grow to 0.8", and the females 1.4".
They
are tiny North American fish, found in weedy, slow moving fresh and
brackish waters from Florida to North Carolina, and were recently also
discovered in Texas. They are not normally found in pet stores, since they
are so small and not too showy, being olive green in colour with a dark
brown line running down the side of their body. Don't say I told you
because it says so in the books, but the males proudly sport very large
gonopodiums!
They
accept all foods but should have some vegetable matter. I feed mine
regular flakes and spirulina flakes, pinched to a small size. They are not
greedy eaters and are rather lazy swimmers, and are best kept in a well
planted small species tank at room temperature in hard, slightly alkaline
water with some tannin. Both adults and young like to hide amongst plants.
The
young are produced continually on a "production line" system
("superfoetation") rather than in distinct broods, and it is
said that adult females can produce one or two fully developed young
almost every day of their adult lives. I acquired a young pair from our
member Matt Hennig a few months ago, and now have well over a dozen.
Despite
being a North American fish, Matt's strain came from Germany. Having kept
them before and liking them, Matt's father bought some in Germany and flew
here with them in a bag in his shirt pocket, aerating the bag every now
and then with a straw!