The part I enjoy most about our hobby is taking care of the babies. I await the arrival of the tiny new ones like an anxious grandmother. I can just about tell, to a day, when the blessed event will take place, much to the amazement of young fish fanciers. Most of our fish are livebearers and my experience concerning the raising of babies is based on this type of fish. They live happily in fish tank – which is fully optimized and cleaned. Few years ago it became simple to achieve good tank condition – follow a good quality fish tank guide and you are in.
There is not much to the trick of knowing when the mother is to give birth if one will take the trouble of taking note of the date of the month the fish previously gave birth. If the fish is in good condition, she gives birth every certain number of days with leeway from a day to ten days or so. About that time of month, I begin to look for other signs such as the shape of her gravid spot and the shape and fullness of her middle.
Some fish get very puffy and as her day approaches, even her chest fills out full almost up to the head and her middle gets quite distended. Others do not get so heavy and it is a little more difficult to tell when they will give birth. With a reflector overhead, I try to look through the fish at the gravid spot. If the cavity at the middle of the fish is filled and is sometimes like a crescent or a triangle in shape, I know that her time is near. In some of the more translucent fish, the embryos or babies can be seen thru the skin at this point. As the embryos develop, the gravid spot becomes larger and clearer and the side of the fish will bulge, particularly when viewed from the top, or looking down on the back.
So that the newly born babies won’t be devoured by the rest of the fish in the tank, I take out the ripe female and place her in a small maternity tank which is thickly planted with micro or dwarf Sagittaria. I also place some floating plants such as Water Lettuce, Myriophyllum, Anacharis, Water Sprite or Water Fern. Other plants that are excellent for this purpose are Nitella, Riccia, Crystalwart, etc. The purpose of the plants, of course, is to protect the babies from the Mother. I find I can save almost all the young when there is a small type of Sagittaria planted in the tank because it affords a hiding place at the bottom of the aquarium where the newly born babies rest before they float to the top. I have found that it is a good idea to give the hungry mother some food – preferably some live food – so that she tends to ignore her young. Sometimes, all my maternity tanks are occupied and that’s when the gallon jars come in handy. The water in the maternity tank can be from four to seven inches deep.
As soon as the mother has finished giving birth, it is best to remove her and place her in an aquarium with other females, which have just been thru the same experience. This will give her a chance to rest and enjoy some live food.
The new babies may stay in the maternity aquarium for a few days, depending on the size of the tank and the number of babies. They are on their own in a short time and can take micro worms, micrograin, or baby manna.
I drop a tiny pinch of baby manna on the water and give the water surface a light tap to teach them to take dry food. In a few days they can eat newly hatched brine shrimp.
The number of babies which can be raised to good healthy, lively fry in three or four months, depends on cleanliness, size of the aquarium and intelligent feeding. Siphoning a few inches of water from the bottom of the aquarium about once a week is not too often. If the aquarium is well planted it is not necessary to do that except when needed
The size of the aquarium that the babies are to occupy during the first few weeks is important. If placed too soon in a large one where they have plenty of swimming space a number of them somehow, get lost, and wander about while the rest are feeding, and therefore, do not get enough to eat. After awhile, they get thin and deformed and eventually die. From a batch of thirty five, there would probably be less than half of that number alive after two months. On the other hand, if the babies are left too long in a small container, they do not get to be vigorous and healthy, nor do they grow. If I do not want to move the babies from one tank to another as they grow in size and need more swimming space, I place them in a ten or fifteen gallon aquarium with about five inches depth of water. As they grow in size, the depth of the water can be increased. The babies grow like weeds, if they are fed properly and intelligently. Adult fish can be fed once or twice a day only, but babies, in order to attain good and fast growth are fed from four to six times a day. If they do not get a good growth in the first three or four months, they will not get to be good-size adult fish. Platies can attain about an inch or over in four months, while swordtails will be an inch and a half in that time.
Before I learned to put the babies on a regular feeding schedule, I sometimes forgot to feed them and at other times, I fed them too often, neither of which is good. Now, they get their light feeding on schedule every three hours, and are thriving on it. Keeping and eye on proper fish tank hygiene is also important.
If all goes well, they will be having a lot of babies of their own in six months.