Raising and Care of Belonesox belizanus:the Pike-top Minnow

by Dan Marentette, CAS

originally published in The Calquarium Volume 43, Number 3, November 2000

I first acquired these fish at one of our local fish storeís 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 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 didnít seem to bother each other and both enjoyed the heat.

I tried to feed frozen foods, white worms, and all sort of other dry combinations but I soon learned that these females had already been spoiled with live feeder fish. Now I donít like to feed using this method as Iím too much of a nature lover to knowingly put live fish into a situation where they will have no choice but to meat 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 letís 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 didnít 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 motherís 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 malesí sperm for a number of months. I had two options: either spend more money on another male ($10.00 CDN); or wait and see. All right, everyone knows (because Iím the club treasurer) that Iím cheap. So next came the waiting game. One morning as Iím 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 leaches in my tank! Just look at them allÖthey must be from that darn fish store, right? Wrong! Well, guess what? They werenít leachesÖ 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 wouldnít bother their own fry or eat them as soon as they were born. But looking into those hungry eyes I wasnít 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 the month, but do 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 loosing 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 low 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 donít need monthly fertilizing as do goodeids. But much to my disappointment the second female hasnít 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 wonít 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 donít worry about chasing the feeders or trying repeatedly to get them. I guess their attitude is that the feeders arenít going anywhere, so weíll 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 of 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 loose 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, itís one of those live bearers; you know, feeders for my cichlidsĒ, 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.