1. Bacterial Infection: Inspect the red patches for any fuzzy or cotton-like growth, which could be signs of a bacterial infection. It can cause skin inflammation and spread quickly.
2. Parasitic Infection: Parasitic infections, such as anchor worms or fish lice, can cause red patches and irritate your goldfish's skin. Look for small, white, or reddish parasites on the fish's body or fins.
3. Skin Injury: If the red patches are localized to a specific area, it may be due to physical damage or an injury. Check the tank for sharp objects or decorations that could have caused the injury.
Losing its Tail:
1. Fin Rot: Fin rot is a bacterial or fungal infection that can cause the tail and fins to deteriorate and rot away. The edges of the affected fins may become ragged or discolored.
2. Tail Biting: Goldfish are known to nip each other's fins, especially if they are kept in overcrowded conditions or with aggressive tankmates. Check for signs of aggression or bullying in the tank.
Fin Clamped Shut:
1. Poor Water Quality: Fin clamping can be a sign of stress, which could be caused by poor water conditions such as high levels of ammonia, nitrites, or fluctuating water temperature. Test your water parameters to ensure they are within the appropriate range.
2. Disease or Infection: Fin clamping can also occur as a response to various diseases or infections. If your goldfish is exhibiting other symptoms such as lethargy, decreased appetite, or unusual behavior, it's important to investigate further.
3. Stress: Prolonged stress can also lead to fin clamping. Make sure your goldfish has a peaceful environment with adequate space, hiding spots, and suitable tankmates.
4. Water Temperature: Goldfish prefer cooler water temperatures between 65-72°F (18-22°C). Water that is too warm or too cold can cause stress and lead to fin clamping.
If you suspect your goldfish has a health issue, it's best to consult with a knowledgeable aquarist, fish veterinarian, or pet store employee for proper diagnosis and treatment.