If you want to get some baby goldfish, the most fascinating way of obtaining them is of course to breed goldfish in your own aquarium or pond. A goldfish becomes sexually mature when it is around one year old, but will not reach their prime until two years later. It can be hard to distinguish a male goldfish from a female goldfish, but when they become mature the female will usually become a little plumper than the male. The male goldfish will develop small bumps on its head, and when the spawning period begins those bumps will be easier to notice since they will become white. There are several things that you can do to encourage your goldfish to produce baby goldfish. Pond living goldfish will typically spawn during spring, when the cold season ends. Frequent water changes can also induce spawning. If you want baby goldfish, you should make a partial water change once a day. The fresh water and supreme water quality will help getting your goldfish into spawning mood. Changing 20 percent of the water is a good rule of thumb, since a larger change can alter the water quality too rapidly. Keep the water temperature around 700 F at day time and around 500F during the night. An improved diet will also increase the chance of baby goldfish in your pond or aquarium. If you usually feed your goldfish pellets or similar, you can gradually substitute the prepared food with frozen or live food such as worms or brine shrimp. A third trick that is commonly used by professional goldfish breeders is to separate male and female goldfish. When you reintroduce them to each other, they will be more interested in making baby goldfish. This method does however mean that you must know which fish that is male and which fish that is female. Providing your goldfish with spawning mops is a good idea when you want to have baby goldfish, since the female goldfish can use these mops to deposit the eggs on. The eggs are adhesive and will stick to the spawning mop. Professional breeders will often make their own floating spawning mops from nylon rope, but you can choose to purchase ready made goldfish spawning mops from the fish store if you don’t want to create them yourself. You know that your goldfish are ready to make baby goldfish when the male starts to chase the female around for several hours. He will bump and push her on the abdomen as soon as he gets a chance. When the female is ready, she will deposit eggs that stick to virtually anything in the pond or aquarium. If you have provided the goldfish with floating spawning mops, she will probably choose to release the eggs near them. As soon as the eggs are released, the male goldfish will spray his milt over them in order to fertilize them. Most female goldfish releases several batches, and the first batch is considered to be of highest quality. A large female goldfish can lay up to 1000 eggs during one spawn, but it is only a fraction of these that will turn into baby goldfish. When you plan to raise baby goldfish, it is important to keep in mind that adult goldfish love to eat baby goldfish, including the eggs. As soon as the eggs have been fertilized, the spawning mops should therefore be removed to their own aquarium or pond.
Rinse the spawning mops in a bucket of water. The water must be suitable for fish keeping, and have the same water quality and temperature as the water in which the eggs were deposited. Then you can place the eggs in a 20 gallon aquarium where the water is no deeper than 6 inches. If you keep the water temperature at 70 degrees Fahrenheit, the eggs will hatch with 3 or 4 days. During this period, you can spot eggs that are not as clear as the rest. It is only the clear eggs that can hatch, and the other eggs should be removed since they will attract fungi. Newly hatched baby goldfish will be too small to feed on anything else than microscopic organisms, but eventually you can start giving them larger and larger food. When the baby goldfish is 48 hours old, you can give them liquid fry food, oatmeal paste or hardboiled egg yolk. After around two weeks, the baby goldfish is large enough to eat infusoria and newly hatched brine shrimp. The next week you can introduce powdered fish food. Do not feed your baby goldfish more than what they can consume within 20 minutes.
During the first four weeks, the need food three times a day. Until they are four moths old, you should feed at least twice a day.
http://www.aquaticcommunity.com/goldfish/baby.php
