Here's a breakdown of what to do and why:
1. Observe and Identify Symptoms:
* Sinking: This could be a sign of many things, including swim bladder issues, internal parasites, or even just being overfed.
* Other Symptoms: Look for other signs like:
* Loss of appetite
* Redness or swelling
* Fins clamped against their body
* Flashing (rubbing against objects)
* Rapid breathing
* Changes in color or behavior
2. Water Quality:
* Test your water: Use an aquarium test kit to check ammonia, nitrite, nitrate, and pH levels.
* Maintain good water quality: This is crucial for fish health. You might need to:
* Perform a partial water change: Remove 25-50% of the water and replace it with dechlorinated water.
* Clean the filter: Regularly clean your filter media.
* Adjust water parameters: If test results show issues, take steps to correct them.
3. Seek Professional Help:
* Contact a veterinarian: A vet specializing in aquatic animals can diagnose the problem and recommend appropriate treatment.
* Visit a reputable aquarium store: They may have knowledgeable staff who can offer advice or help with water testing.
4. Quarantine:
* Isolate sick fish: To prevent the spread of disease, separate your sick goldfish from others.
5. Treatment Options:
* Veterinarian-prescribed medications: Your vet may prescribe medications for parasites, bacterial infections, or other issues.
* Over-the-counter medications: Some aquarium stores sell over-the-counter medications, but always consult with a professional before using them.
6. Supportive Care:
* Temperature: Keep the aquarium water at the proper temperature for your goldfish species.
* Feeding: Offer a balanced diet of high-quality goldfish food.
* Stress Reduction: Minimize stress for your fish by providing a peaceful environment.
Important:
* Never use medications intended for humans on your fish.
* Be patient and follow your vet's instructions carefully.
I'm not a veterinarian, so this information is for general guidance only. Please consult with a professional for accurate diagnosis and treatment.