25.5.12
Platys, Swordtails, Mollies and Guppies -- these four popular livebearing fishes pose only one problem when it comes to breeding - where are you going to put all the baby fish? Bear in mind that the record for a Swordtail is around 300 fish, and this could be repeated within a month without the female having recourse to a male Swordtail either, then you can visualize just what could happen once you start breeding fish. But let's follow the course of events.
By now you will have become very familiar with the male livebearer's constant chasing and showing off to the female of his choice (or any other female member of his species that just happens to be passing! You have to be very observant and almost in the right place at the right time to see the actual moment when fertilization occurs, it's that quick.
Soon, the female fish begins to show the effect of the male's brief visitation; her belly begins to swell and often a dark area appears just around the area of her vent. In some cases, the skin of her body becomes stretched so thinly by the number of young fish developing inside her that you can actually see their eyes showing through.
Like all ladies in a 'certain condition' life can become stressful for the female, who may still be pestered by the attentions of male fish. Hopefully, it may be that the aquarium has sufficient aquatic plant life for her to be able to hide away for some respite and this same plant covering may well act as a sanctuary for any young fry once they emerge from their mother's body.
The female delivers the young fish after about 30 days. Naturally you will want to save as many of them as possible from being instant food for the other fish in the aquarium - or even their own parents. How to do this can be solved in two ways. One method is to place the female (now referred to as being gravid, rather than 'pregnant') in a small confining tank floated inside a bigger tank. Her tank has small slots in it so that the young fish can swim out into the larger water space and escape any tendency she may have to eat them. This is fine in theory but in practice things can go wrong, especially if you move the female into these small quarters at the wrong time, i.e. too near to the end of her 'confinement' period.
Stress of the move may well cause her to abort the youngsters prematurely and they will not survive. There is no point either in floating the 'breeding trap' tank, as it is called, in the community aquarium itself for all that will happen, even if the female goes to full term, is that all the other fish will queue up under the trap for a continuous supply of live food.
As you need a separate tank to use the breeding trap correctly, the best plan would be to use this smaller tank as a nursery tank. Don't forget, you've hopefully still got that quarantine/hospital tank somewhere that would do admirably. The quarantine/hospital tank need not be spacious, anything above 25 cm (10") long will suffice.
The best scenario for our expectant lady will be in a well-planted tank. The 'well-planted' description does not necessarily mean artistically planted as might be the case in the main aquarium. All that is needed is enough shelter for the baby fish, there will be no hiding places required for mum as she will be the only adult fish in the tank. A certain number of tall plants around the tank in clumps together with some bushy types and a good covering of a floating species (Riccia is fine) or Indian Fern, Ceratopteris thalictroides, with its tangle of roots tangling down into the water will give the youngsters the safety areas they require.
You should keep an eye on the female to check that she is progressing well; you can transfer her into the 'delivery tank' as soon as you see that she is gravid - the earlier the better.
You will know when she has delivered her young as she will lose her fatness in the belly region. Now, it is up to you to decide how long you will leave her to recuperate in the quiet nursery tank before returning her to the main aquarium. Of course, you won't want her seeking out her offspring so feed her in the usual way. Should she take an interest in looking for the baby fish then you have no alternative but to return her to the main aquarium.
Livebearer fry are more capable than most new fishkeepers realize. There is no need to feed them microscopic particles of food; they will attack flake food quite voraciously, although crumbling up the larger flakes might help them out a little.
'Fry food' and 'growth food' are usually higher in protein than the normal flake food and are specifically formulated for the feeding of young fish. You should supplement this with live food if at all possible. Newly-hatched Brine Shrimp is excellent, as is the use of Grindal-worm and White-worm.
From now on, it's a case of growing on the young fish. Frequent partial water changes will help keep them healthy, active and growing. Splitting up the numbers may be necessary if the nursery tank becomes too small (or you want to use it for another purpose). Some quality control may need to be done with any weak or malformed fish being discarded; you may, if so inclined, or if the color strain of the fish is to be preserved (or improved), segregate those of suitable coloration for future breeding, isolating them from any color strain which would otherwise weaken the quality of the strain you are trying to develop.
For those fascinated by permutations, the Mendelian Laws of Heredity can make interesting reading. To give but a taste: breeding a female Guppy of wild coloration with a male Gold Guppy will produce a first generation of Guppies all with wild coloration because of the dominance of the wild coloration gene. However, moving on to breed between these offspring the results for the next generation will be 25 per cent wild coloration (pure), 50 per cent wild-type coloration (through dominance) and 25 per cent Gold (pure).
You can see that attempting to produce a 'new' color strain is not just a case of blue and yellow will equal green but probably all the shades in between. Add to this the extra complications that arise should you also wish to develop, say, finnage refinements and body shape modifications as well as color then you're in for a very long haul. Time to reach for the calculator and order all those extra tanks!
By now you will have become very familiar with the male livebearer's constant chasing and showing off to the female of his choice (or any other female member of his species that just happens to be passing! You have to be very observant and almost in the right place at the right time to see the actual moment when fertilization occurs, it's that quick.
Soon, the female fish begins to show the effect of the male's brief visitation; her belly begins to swell and often a dark area appears just around the area of her vent. In some cases, the skin of her body becomes stretched so thinly by the number of young fish developing inside her that you can actually see their eyes showing through.
Like all ladies in a 'certain condition' life can become stressful for the female, who may still be pestered by the attentions of male fish. Hopefully, it may be that the aquarium has sufficient aquatic plant life for her to be able to hide away for some respite and this same plant covering may well act as a sanctuary for any young fry once they emerge from their mother's body.
The female delivers the young fish after about 30 days. Naturally you will want to save as many of them as possible from being instant food for the other fish in the aquarium - or even their own parents. How to do this can be solved in two ways. One method is to place the female (now referred to as being gravid, rather than 'pregnant') in a small confining tank floated inside a bigger tank. Her tank has small slots in it so that the young fish can swim out into the larger water space and escape any tendency she may have to eat them. This is fine in theory but in practice things can go wrong, especially if you move the female into these small quarters at the wrong time, i.e. too near to the end of her 'confinement' period.
Stress of the move may well cause her to abort the youngsters prematurely and they will not survive. There is no point either in floating the 'breeding trap' tank, as it is called, in the community aquarium itself for all that will happen, even if the female goes to full term, is that all the other fish will queue up under the trap for a continuous supply of live food.
As you need a separate tank to use the breeding trap correctly, the best plan would be to use this smaller tank as a nursery tank. Don't forget, you've hopefully still got that quarantine/hospital tank somewhere that would do admirably. The quarantine/hospital tank need not be spacious, anything above 25 cm (10") long will suffice.
The best scenario for our expectant lady will be in a well-planted tank. The 'well-planted' description does not necessarily mean artistically planted as might be the case in the main aquarium. All that is needed is enough shelter for the baby fish, there will be no hiding places required for mum as she will be the only adult fish in the tank. A certain number of tall plants around the tank in clumps together with some bushy types and a good covering of a floating species (Riccia is fine) or Indian Fern, Ceratopteris thalictroides, with its tangle of roots tangling down into the water will give the youngsters the safety areas they require.
You should keep an eye on the female to check that she is progressing well; you can transfer her into the 'delivery tank' as soon as you see that she is gravid - the earlier the better.
You will know when she has delivered her young as she will lose her fatness in the belly region. Now, it is up to you to decide how long you will leave her to recuperate in the quiet nursery tank before returning her to the main aquarium. Of course, you won't want her seeking out her offspring so feed her in the usual way. Should she take an interest in looking for the baby fish then you have no alternative but to return her to the main aquarium.
Livebearer fry are more capable than most new fishkeepers realize. There is no need to feed them microscopic particles of food; they will attack flake food quite voraciously, although crumbling up the larger flakes might help them out a little.
'Fry food' and 'growth food' are usually higher in protein than the normal flake food and are specifically formulated for the feeding of young fish. You should supplement this with live food if at all possible. Newly-hatched Brine Shrimp is excellent, as is the use of Grindal-worm and White-worm.
From now on, it's a case of growing on the young fish. Frequent partial water changes will help keep them healthy, active and growing. Splitting up the numbers may be necessary if the nursery tank becomes too small (or you want to use it for another purpose). Some quality control may need to be done with any weak or malformed fish being discarded; you may, if so inclined, or if the color strain of the fish is to be preserved (or improved), segregate those of suitable coloration for future breeding, isolating them from any color strain which would otherwise weaken the quality of the strain you are trying to develop.
For those fascinated by permutations, the Mendelian Laws of Heredity can make interesting reading. To give but a taste: breeding a female Guppy of wild coloration with a male Gold Guppy will produce a first generation of Guppies all with wild coloration because of the dominance of the wild coloration gene. However, moving on to breed between these offspring the results for the next generation will be 25 per cent wild coloration (pure), 50 per cent wild-type coloration (through dominance) and 25 per cent Gold (pure).
You can see that attempting to produce a 'new' color strain is not just a case of blue and yellow will equal green but probably all the shades in between. Add to this the extra complications that arise should you also wish to develop, say, finnage refinements and body shape modifications as well as color then you're in for a very long haul. Time to reach for the calculator and order all those extra tanks!
