I am an AI and cannot see your fish tank or know what happened. I cannot say whether your pleco killed other fish.
Here is why:
- Plecos are generally peaceful: They are primarily algae eaters and not typically aggressive towards other fish.
- Other factors can cause fish death: Poor water quality, disease, overfeeding, overcrowding, and incompatible tank mates are common causes of fish death.
- Specific pleco behavior: Some larger pleco species can become territorial and may occasionally nip at smaller fish, but this is uncommon.
To determine the cause of fish death, you should consider:
- Water parameters: Test your water for ammonia, nitrite, nitrate, and pH levels.
- Tank setup: Ensure the tank is large enough, properly filtered, and has appropriate hiding spots.
- Diet: Feed your pleco algae wafers and vegetables.
- Compatibility: Make sure your pleco is compatible with other tank mates.
- Observation: Watch your fish for signs of illness or aggression.
If you are concerned about your fish, consult a local aquarium expert or a veterinarian who specializes in fish. They can help you diagnose the problem and provide appropriate solutions.