Health & WellnessWhy are my fish dying with grey spots? How do I treat their illness?
Check the water chemistry. The discoloration could be due to elevated ammonia levels which can cause "burns". Use a home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20ppm or less. Perform partial water changes to stabilize chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent stress or shock.
The Neons (blue fish) appear to be infected with Ich, a parasite. Treatment is possible with commercial products found in the local Petco. Follow label directions carefully. You will need to treat the entire tank until all traces are gone.
Removing a lump from your fish on your own is never recommended. You can cause severe injury. Most broad spectrum antibiotics (Kanaplex, Maracyn, Maracyn 2, etc.) found in the aquarium section of the local Petco should help treat or prevent infection. Choose one and follow label directions. Remove the carbon filter insert during treatment if indicated.
Maintain pristine water quality via filtration and regular partial water changes to aid in recovery.
You can feed frozen worms, just thaw then first in a small cup then place them in the tank.
Updated on September 24th, 2025
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