Congrats! Your fish have found their environment to their liking and have begun to breed.
This short article explains some to the methods that you can use to harvest the fry and grow up the little cichlids to turn into healthy, thriving adults.
Lake Malawi cichlids are maternal mouth brooders. In other words, the female lays the eggs, has them fertilized by the male and takes them into her mouth to hold for several weeks until which time the eggs hatch and the fry are ready to be released. Typically, females hold from 2-4 weeks. During this time, the female eats very little or nothing at all. You can tell she is holding by looking at her enlarged buccal cavity (throat area) and her mostly closed mouth. The eggs hatch at around 1 week and develop into fry. At around 2 weeks, the fry have pretty much absorbed their egg sacs that provide them with nutrition during their first stages of life.
When the female releases the fry depends on many factors including age (of the female), species type, her health, her hunger, the water conditions in the tank, the water temperature, etc., but in most cases, this occurs before 4 weeks have past. There are several methods you can employ to harvest the fry and raise the little cichlids to maturity.
With the first method, you can leave the female in the main tank and let her spit the fry out naturally. The fewer the number of other adult fish in the tank and the more shelter provided, the greater the chances of fry survival. Remember, it is up to you to provide these conditions to increase the fry's odds. This method is the most natural, however tends to lessen the chances for survival for the little fry. Additionally, this method creates more stress on the female as she has to fend off males and other fish that wish to make the fry a snack.
The second method is to remove the female from the main tank and transfer her to an unoccupied tank where she can release the fry when she is ready with no fear of other fish eating them. This way allows you to save the majority of the fry and lessen the stress on the female. Once in the tank, the female may spit the fry and let them roam for food and quickly take them back as soon as anyone approaches the tank. She may do this for some time until she feels the fry can fend for themselves. It is rare that a female eats her own fry, however this can occasionally happen. For that reason, it is a good idea to remove her after she has spat and take her back to the main tank or a recovery tank to gain some of her weight back. Then you can raise the fry in their own tank without the worry of losing them to other bigger fish.
With the third method, you can strip the fry from the female. This involves catching the female and transferring her to a bucket half full of her own tank water. With her in the bucket, gently hold her in your palm under the water. Make sure you do not cover her gill plates so she can still breath. Using either your fingernail or a fine tool like a toothpick or pencil, gently pry her mouth open by pressing on her lower lip. This will allow the fry to escape out of the mouth and into the bucket. You can check if most of the fry are out of the female's cavity by lifting her out of the water and looking in her mouth. A strong light may help to see better. After the fry are stripped, you can return the female to the main tank or to a recovery tank. Stripping is best done after the female has held for at least 2 weeks. That way the eggs have hatched and the fry are mature enough to take easy care of. You can either transfer the fry into their own tank or into a breeder cage to raise up until they are large enough to release into another tank. Stripping fry is often useful when a female is immature and known to spit prematurely or just does not hold to full term regardless of age. Stripping also ensures that the fry do not get eaten by either the female or other tank mates.
A final method is to strip the eggs from the female after they have been fertilized. This method requires that you artificially incubate the eggs in an egg tumbler. This device aerates the eggs so that they hatch properly. Stripping the eggs is done the same way as stripping the fry, but done as soon as the mating ritual is complete and the female has a mouth full of eggs. This method tends to result in the most fry when done properly. It is useful when the female is known to spit prematurely or swallow her eggs. The eggs in the tumbler typically hatch within a week and are well developed fry before the 3rd week is up.
Once the fry have been separated from their mother and are mature enough to accept food, make sure you feed them often. Most fry will accept finely crushed flake food and/or live/frozen brine shrimp as soon as they have absorbed their egg sacks. See Food for Fry for more options and information. Fast, healthy growth in fry depends on many factors but most importantly, good water conditions, a large tank, frequent feeding, proper diet and adequate lighting. Most Malawi cichlids are well capable of breeding once a month so be prepared and enjoy your fry! □