Raising and Care of Belonesox belizanus
the Pike-top Minnow
by Dan Marentette, Calgary Aquarium Society
originally published in The Calquarium Volume 43, Number 3, November 2000
Aquarticles
I first acquired these fish at one of our local fish store’s opening. They caught
my eye because they were unusual and very rarely seen locally, and they looked big and
mean. These fish could almost be in the same class as the bruisers of the cichlid world,
but to my liking they are LIVE BEARERS. They come from Central America; specifically
southern Mexico, south to the Honduras. They do very well in Calgary hard water and thrive
in hot temperatures, as high as 35C. The females grow very long, and can go up to 20cm in
length, with the males about half that size. So they need a large tank with good plant
coverage and space to roam.
I bought two females and one male and happily put them in a 120-liter tank by
themselves at around 25C. But to my dismay they very quickly got some fungus growing on
those very long, large mouths; and they seemed to be listless. So into the literature I
went to find out anything I could about these fish, but very little could be found. So
onto the Internet I went, and again the same lack of information. I decided to add some
salt and up the temperature to 30C. Within a week all was well with the females, but I
lost the male and the females looked hungry. The two females were sharing a tank with a
large discus and didn’t seem to bother each other and both enjoyed the heat.
I tried to feed frozen foods, white worms, and all sorts of other dry combinations but
I soon learned that these females had already been spoiled with live feeder fish. Now I
don’t like to feed using this method as I’m too much of a nature lover to
knowingly put live fish into a situation where they will have no choice but to meet their
maker. But after much deliberation I gave in and finally fed them their choice in life.
Now I have been told that if you can get fry from day one you can train them to eat other
(non-living) diets. Ah: a challenge for me to see if this is possible. I have already had
this success with my oscars so let’s see if these bad girls can also be changed. That
would mean starving them for at least a while, but this is risky, and remember I had lost
the male and I didn’t know if my two females were pregnant. As with other types of
large live bearing species that have monster fry, it is sometimes very hard to tell if the
females are gravid due to their size and the way the fry lay lengthwise in their
mother’s womb. So back to the Internet and the books to find out all I could about
the breeding of my new live bearing bruisers.
Again very little seems to be written about how long it takes for them to give birth,
or how they breed, or even if the females carry the males’ sperm for a number of
months. I had two options: either spend more money on another male ($10.00 Canadian); or
wait and see. All right, everyone knows (because I’m the club treasurer) that
I’m cheap. So next came the waiting game. One morning as I’m doing their morning
feedings I notice these small, thin, stick-like objects floating around in the hornwort.
Oh no, I thought to myself, I have leeches in my tank! Just look at them all…they
must be from that darn fish store, right? Wrong! Well, guess what? They weren’t
leeches… they were pike minnow fry and they were huge! At least 1cm to 2cm long.
There were about 25 fry, all hanging out in the hornwort and dashing around very quickly
every time I went near them. I did find some info that indicated that the females
wouldn’t bother their own fry or eat them as soon as they were born. But looking into
those hungry eyes I wasn’t taking chances. Out the fry came and all are happy.
A few days later there was more fry, from the other female. Again, there was around 25
fry from this second batch. Out they came too. Now these fry are in small show tanks (5
liters) and its time to test them out with other types of food. It did take a couple of
days but soon they were eating frozen foods and white worms. They love to chase white
worms around on the bottom of the bare tank. The next question to be answered was "do
the females need a male to fertilize them again every month as do the goodeids, or do they
carry the sperm packs for a few months, as do other poeciliids?" I spent a long
month waiting for these answers.
But back to the children. They did very well for over a month, but due to technical
difficulties with Trans Alta Utilities and the electrical supply to my home, I lost one
whole tank of fry and half of the other tank before we got back the power. BOO HOO. I also
noticed that some of the smaller fry were losing pieces from their tails and the larger
fry had very fat tummies. Watch out! It looks like we have a case of big fish, little
fish. So I started to feed more often and larger amounts and gave them more room to run
away and hide.
The end of the month comes along, and lo and behold I see another batch of fry, but
this time only eighteen in number. So there is my answer: females do carry the male sperm
for a few months, and don’t need monthly fertilizing as do goodeids. But much to my
disappointment the second female hasn’t dropped any more fry, and now a few months
later, both females are not dropping.
The fry are growing well in larger tanks. They are still being fed non-living food.
Some interesting things about the original females are that they won’t eat anything
but live food, no matter how long I starve them. They seem to only hunt and eat at night
when the lights are off. Their hunting style is to hide in the plants at the top, then
quickly dash out at the feeders, trying to grab one in one fell swoop. Sometimes they get
their mouths full and sometimes they totally miss. But it seems that their hunting is a
single hit or miss procedure, and they don’t worry about chasing the feeders or
trying repeatedly to get them. I guess their attitude is that the feeders aren’t
going anywhere, so we’ll try again in a little while.
Hopefully in a few months the fry will start breeding and I can continue to see if I
can keep them completely off live fish as food. There are some interesting black colorings
on the tails of the fry. This could be the differences in the sexes when young, but as
they grow older they seem to lose these markings. There already is a size difference
showing, which is certainly indicating that the young females are starting to show their
growth difference over the young males.
The two moms are still happily awaiting some male companionship and are easily sharing
their home with the large discus. But be aware that anything small enough to fit into
their large mouth is certainly fair game to them.
So if any aquarist would like to have one of the flesh eating, large mouthed, big
bruiser type fish with an attitude, and are tired of the cichlid people saying "Ah,
it’s one of those live bearers; you know, feeders for my cichlids," just show
them one of these big babies that look like alligators and a new respect for live bearers
will certainly not be far behind.
Other aquarium clubs and non-profit organizations can use this, or other articles,
in their own journals or web sites, provided that credit is given to the author, the
Calgary Aquarium Society, and The Calquarium. In the case of a reprint in a hardcopy
publication, two copies of the published work are sent to the Calgary Aquarium Society at
its mailing address. And in the case of a reprint in an Internet publication, a link back
to the original article site must be provided in a prominent location. |