Breeding the Four Common Live Bearing Tooth Carps

Author:  Curtis B

Date submitted : 4-24-2004 

Picture of a male "Brick Red Wag Lyretail Sword"

Introduction

The four common live bearing fish, namely the Molly, the Sword Tail, the Platy Fish and the Guppy are some of the most delightful, easy to keep and breed of all the tropical fish that are kept in aquaria. This article is written to divulge tips and recommendations for the promotion of raising the fry to sell back to your local pet stores. The fish coming out of the farms and sold in pet stores are weak , and sickly. The proper propagation of  their young, by hobbyists that care, should give them back the good name they deserve and once had. I hope that this article can help people that read it, to get over three of the most problematic parts of raising fry, which are diseased starter fish, getting larger fry and growing out the fry to salable size in just 2 months.

Choosing Breeding stock

Attaining breeding stock is hard, but not impossible. Here are some very important tips to consider.

1. Stick with a single color morph - This will make your lines easier to control.

2. Genetic diversity - You do not want to start with all fish from the same tank. nor even similar color morphs from the same months. The likelihood that these fish came from the same spawning pond is relatively high, even when purchased at different stores in your local area.

3. Look for fish that are healthy. even if they came from a sickly tank. These will be more disease tolerant fish

4. Buy about 10 to 15 fish with similar color traits that you wish to isolate into your new line - 3 males and the rest females. Hopefully you will get one or two good virile males and several good birthing females from this first group.

5. First try to treat the fish for any apparent disease that manifests itself. The most common one seems to be a wasting disease where the fish has clear poo and quits eating. The most effective treatment I have found so far is immediate isolation and eventual euthanasia to protect the rest of the stock from getting the disease. The other most common parasites are Velvet and ICH which can be treated easily with commercial remedies. To identify external parasites, just watch the fish to see if they are "flashing" off objects. I utilize the "All in method" so that I only have to treat the group once. After you have a viable population you should follow strict quarantine procedures if adding any new fish to your breeding line.

6. Some male morphs are not good at mating. Two examples might be the extra fancy finned guppy that has trouble catching the female due to the long fins slowing it down, and the male lyre tailed swords who's gonopodium are to long to be of any use.

Setup Your Tank and The Great Salt Debate

Depending on your choice of species, you will need to accommodate their full grown size. Most female Molly's get the largest at about 4 to 5 inches or 10 to 12.5 cm but I have seen them larger. The next largest is the Swordtail ranging around 3 inches or 7.5 cm. The Platy is about 2 inches long or 5 cm and the small Guppy is only about 1 inch or 2.5 cm long. ( all numbers exclude tail finnage)

Adding salt to your tank water  is a great debate, but one thing to keep in mind is that the fish in this group live in greatly varied conditions in their natural habitats and are very adaptable. Everything from full brackish conditions to full soft water. No matter what people tell you, brackish water is not some sort of fake recipe such as " One table spoon ( 15 ml ) of "aquarium salt" ( dehydrated seawater)  for every 5 US gallons of water ( 20 liters ) . Full brackish would imply somewhere in the range of 15 parts per thousand or about 1.01 specific gravity Anyways, that controversial topic aside, you should consult with your local fish store where you are purchasing your stock in order to know exactly how they are keeping the fish, so that you can determine just how much acclimation is needed to get them adapted to your tank conditions. Sea salt also adds some hardness to the tank water which can raise the pH. Acclimation is the most important part of getting these fish to do well in your tank water, but don't be afraid to use salt at first to ween them off of it later down the road. The more gradual you makes these changes to their environment, the happier they will remain. Just as an example, I have acclimated my breeding stock down to pH ranging between 6.6 and 7.2 with zero salt added to the water in the past two years. Hardness in the spring time goes down to less than 5 ppm in both GH and KH and goes up to 30 ppm in the late fall. I would consider these to be very extreme soft water conditions for these fish, if you believe what you read elsewhere on the internet. Yet my fish produce copious broods of young, year round, and I rarely lose a fish due to illness anymore.

Reproductive Biology

There are many different methods of catching and raising fry, but since I am limited in space, I will just talk about two methods that I found to be the most successful due to trying out most of the other common ones.

Birthing tank

 One of these is just to watch your females and get good at learning the signs when she is getting ready to give birth. Then place her in a small tank that has lots of Java Moss and other plants that float like Horn Wort inside it. (SEE PICTURE) To identify when your female is about ready to give birth you look for these signs. Heavy breathing. lack of appetite, hiding more than usual.  She remains fat even before feeding time. She starts to "square off" and not look quite as "round" anymore. Her Anal vent may also look distended. Place her in the birthing tank with proper acclimation and wait until you see her give birth, them immediately remove her from the fry tank. If your parent tank and the birthing tank match closely in temperature and pH then no acclimation is necessary. Here are Fry 2 weeks Old in Birthing tank

Automatic fry trap tank

In this system, you divide a tank to make a smaller nursery section and pump water from the parent side of the tank, into the nursery side of the tank. This system ( SEE PICTURE ) is composed of three primary parts. 1. A solid tank divider made from glass or thick acrylic. 2. A PVC pipe with 1/4 inch holes drilled  all along the top of it about every 1/2 inch or more and 3. a small power head with a sponge attached to keep the fry from being sucked into it..  (Another Picture)  (And Another)

Basically the filter pumps water from the nursery side of the divider, into the parent side of the divider. This action creates negative pressure in the nursery side and the water refills the nursery by flowing  into the holes drilled in the PVC pipe and back into the nursery section. I should also state that there is a hole drilled through the divider at the lower back corner of the tank to push the PVC pipe end through. If you use the power head setup there is another hole drilled near the back top of the divider. With the HOT filter this top hole becomes unnecessary because you can place the HOT filter to split the divider as to run the water to the parent side. From experience I will tell you that designing and fabricating such a tank empty and dry is the best approach as it will allow you to silicone the glass divider in place which is necessary to keep the divider from collapsing. If the water level drops too low in the nursery side then you have a few options. You can either lower the flow rate of the power head, or you can make more holes in the PVC pipe to allow for more water flow. Use a small diameter gravel bed, so that fry can not bury themselves into gravel cracks. Place stones like polished river rocks over the top of the PVC pipe to hide it and also to attract the fry to the rocks as a nice hiding place.

Here is a picture of my 5th version of the fry trap tank with acrylic custom made panels set into place using silicone. Basically works with the same concept as described above.

Growing Out Fry Quickly

The fry seem to do the best in a higher lighted planted tank with 10+ hours of light per day. Allow algae to grow on the back wall and have plenty of floating plants in at least one corner where the fry can surface and feel safe. Water changes should be regular and it is recommended that you keep gravel thickness very thin under the fry as you do not want to have to gravel vacuum around the fry, nor do you want them to suffer from a large buildup of waste. A tight very small diameter substrate or a thin layer of sand are also both good options. This will give you both beauty as well as function. If you see and fin rot in the first few weeks, this is most likely due to too much pollution. cleaning the tank and treating with Mela fix works wonders. If you raise the fry in a bare bottomed tank then Java moss and floating plants are very helpful

Between feeding off micro organisms off the plants and the algae off the back wall, your fry will be very happy. For added protein, I prefer to hatch Baby brine shrimp at least every other day to feed them. The excess BBS, I feed to the parents who also love BBS. The days that I do not feed the BBS, I will feed commercially prepared food like finely dusted flakes and perhaps a bit of "fry bites" made by HBH - I am also told the "first bites" made by Tetra is a good treat. And another tip - let them eat until they look fat rather than the 5 to 10 minute rule. Fry take longer to find and eat food than adult fish, so give them time. Turning off filter for a half hour during feeding time is very helpful so that food is not wasted and the fry do not have to struggle to get to it.

See my article on baby brine shrimp HERE

Selling Your Juveniles 

I find that independent retailers are much more accepting of locally raised fish than big chain stores. There are great benefits for them to accept them, since they are less likely to be diseased, stressed nor do they have to pay the additional expensive shipping costs to receive them. Because they carry these healthier fish, they will gain a more loyal client list and lose less fish to illness before selling them. Don't expect to get a large amount for each fish. 25 to 33% of the stores sales price is probably fair. To be equally fair to the fish store you should also not try to bring in fish that are too small, sickly looking or just plain ugly. It is a breeders job to carefully cull out belly sliders, weak or deformed fish. Cross breeding different color morphs can really result in some dull Grey looking fish sometimes and trying to sell those might result in losing the confidence of the place where you are trying to market your fish. Use your good sense, because you know what looks appealing and what does not

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Happy Breeding!