The reasons why guppies are holding back their babies:

1. After the fish becomes pregnant, it should be kept separately from other mixed fish to avoid collision with other fish. This leads to the occurrence of dystocia.

2. If the water temperature in the tank is not suitable or the water quality is too poor, they will not grow. Water temperature will affect the functions of the fish's body, and water quality will affect the physical and mental state of the fish.

3. Newly born young fish are easily eaten by big fish as bait, and it will be difficult to find them if you don’t pay careful attention. If the small fish is eaten, it will mistakenly think that it has not given birth yet.

4. It may also be because the environment during pregnancy is not suitable. You need to rest slowly, don’t frighten it, and wait patiently for it to give birth.

What to do if a guppy is holding back and not giving birth:

1. After the female fish gives birth, the tank should be separated immediately to prevent the young fish from being eaten.

2. During this period, you should rest slowly and don't frighten it.

3. Adjust the water temperature to about 35°C to keep the water clean and provide food in a timely manner. After the water temperature stops changing, use a heating rod to raise the temperature. It will soon produce under the stimulation of temperature. Use a heating rod to heat up the water. After the temperature reaches about 30°C, let the water cool down naturally.

4. If the embryo is not mature, you can put a male guppy in the fish tank. Allowing it to swim quickly while being chased by the male fish will help promote embryonic development. However, be careful to fish out the male fish after chasing to prevent him from harming the female fish.