Little Fish With Big Names
By Larry Jinks
The two major groups of livebearers in the
aquarium hobby are the Poeciliids and the Goodeids. Most
hobbyists are familiar with the guppies, mollies, swordtails
and platies so common in the hobby. I can remember
raising green swordtails and black mollies when I first had
tropical fish in the 1960’s. Raising livebearers and
watching the babies being born were popular pre-Nintendo
activities.
When I got back into the aquarium hobby in 1994, I
began with a pair of green swordtails purchased at the
NJAS spring auction. Some guy named Bob Larsen
brought them into the auction.
My first entry into the NJAS Breeder Award
Program was the fry of silver lyretail mollies in July of
1994. I followed these with guppies, platies and swordtails
in the fall and was up to a whopping 20 points in the BAP
standings. I had never even heard of a Goodeid in the fall
of 1994 when George Savapolous brought in Xenoophorus
captivus to an NJAS monthly auction. I would eagerly look
forward to the NJAS meetings to find new species of
livebearers to work with because “I can’t spawn cichlids.”
(a story for another article) I asked people around the
auction table what these fish were and were told they were
Goodeid livebearers. What the heck, a livebearer’s a
livebearer, right? I won the bidding and went home with
my new prize.
With my little fish with a big name safely
swimming in their own tank, I began to research
Xenoophorus captivus. Oh my God! What did I get myself
into? These fish don’t have the familiar gonopodium of the
familiar livebearers and have a gestation period
approximately twice as long as guppies. Their babies are
how big when born?
It seems the Goodeid livebearers are all native to
Mexico. The males have a notched anal fin called an
andropodium to transfer the sperm to the female. These fish
do not exhibit the superfoetation of the Poeciliids and the
female must be fertilized for each brood of fry. The females
have a gestation period of about eight weeks and produce
about one to two dozen fry that average 1.5 to 2 centimeters
long at birth. The fry are nourished in the female through
extensions from their abdomen called trophotaenia (feeding
ribbons). The embryos actually derive nourishment from
the female with these structures and are not reliant on a
yolk sac. In newly born fry you can still see the
trophotaenia trailing form the abdomen, but they soon
disappear.
My latest batch of Xenoophorus captivus came from
ALA chairman Rit Forcier in a fish swap last October. I
kept them in a 30 gallon tank with some crushed coral on
the bare bottom. These fish are not particularly fussy and
do best with slightly alkaline (pH 7.0 – 8.0) and moderately
hard water. They feed on flake, pellet, live and frozen foods,
but should have a vegetable component to their diet. I use a
vegetable flake regularly and even throw in a piece of
parboiled zucchini that I normally reserve for the albino
Ancistrus.
I acquired some Zoogoneticus quitzeoensis at the
Potomac Valley AS auction in October 2003. Jack Borgese,
Frank Nell and I had gone down to their show and auction
and had a great time. These Goodeids were donated to the
auction by John Mangan, a noted Goodeid breeder in the
Potomac Valley club. I quarantined them in a ten gallon
tank and later moved them to a 55 gallon by themselves.
They quickly adjusted and produced by March of 2004.
With the aid of some Java moss on the bottom and some
floating plants at the surface, the fry develop without being
eaten by the parents. I soon had a thriving colony which fed
on a variety of foods including vegetable flake and turned
in fry for points in June. Unfortunately, I arrived home
from vacation in August and found the entire tank wiped
out, probably due to poor water conditions.
I have also worked with Zoogoneticus tequila. I
picked up my first trio at a Norwalk AS auction in October
2003 and had success with them in a twenty gallon setup
with crushed coral. They didn’t produce many fry and I
raised up only eight which I turned in to the North Jersey
AS Breeders Award Program. The trio really didn’t
produce any more young. As they were very large when I
got them, maybe they were too old.
I obtained more Zoogoneticus tequila from both Rit
Forcier and Tom Crane of the ALA in October 2004. These
I had set up in a 10 gallon tank with crushed coral and Java
moss (why mess with success?). They fed happily and
produced fry which I brought in to the Jersey Shore AS
Breeder Award Program in April 2005.
I currently maintain breeding populations of at least
six different Goodeid livebearers and would like to see
more people working with them. If anyone is interested
they can see me at a meeting or contact me to obtain some
of these fascinating livebearers.