First, make sure that the earthworms are free of pesticides or other chemicals. You can do this by buying them from a reputable source or by collecting them yourself from the wild.
Second, rinse the earthworms thoroughly before feeding them to your goldfish. This will help to remove any dirt or debris that may be attached to them.
Finally, only feed your goldfish a small amount of earthworms at a time. Earthworms are high in protein, so too much can cause your goldfish to become overweight or develop digestive problems.
As a general rule, you should only feed your goldfish earthworms once or twice a week. If you have any concerns about feeding earthworms to your goldfish, you should talk to your veterinarian.
Here are some tips for feeding earthworms to your goldfish:
* Use a pair of tongs to hold the earthworm while you drop it into the water. This will help to prevent your goldfish from getting injured.
* If your goldfish are shy, you can try burying the earthworms in the substrate. They will be more likely to find them this way.
* Earthworms are a great way to add variety to your goldfish's diet. They are also a healthy and natural food source.