Why your Chromis may not be eating

Chromis eat copepods

There are a few reasons why your Blue-Green Chromis damselfish aren’t eating. Two of the most common are stress and disease.

If your Chromis isn’t eating the food you are providing then try something different. They usually love mysis and other frozen foods such as brine shrimp and bloodworm. As they are omnivores, it would be a good idea to add Nori (dried seaweed) as another choice.

If changing their diet doesn’t work then consider placing the Chromis in a quarantine tank. If it is stressed then, much like humans, the time out will hopefully get them back on track.

Unfortunately there could be something else bothering them. Below are a few of the most common diseases that affect Chromis.

Diseases that commonly affect Chromis (Chromis viridis)

The most common diseases to affect blue-green Chromis are:

  • White spot (Cryptocaryon irritans)
  • Uronema (Uronema marinum)
  • Marine Velvet (Amyloodinium ocellatum)

White Spot

White Spot, or Marine Ich, is a common stress related disease. You can read more on White spot here.

TREATMENT: Copper treatment in a quarantine tank or a tank with no invertebrates.


Uronema is identified by red sores or white patches on the fish’s body. Any fish affected with this parasite will look agitated and rubbing themselves against rock surfaces. This provides both relief and an attempt at ridding themselves of the parasite.

TREATMENT: Formalin (Formaldehyde) baths and an antibacterial polymer such as Seachem Focus

Marine Velvet

Marine Velvet can look very much like white spot, or ich, but the spots are round with Velvet as opposed to an oval with ich.

Unfortunately with Velvet, once it is in your tank, it will more than likely affect all the fish in your aquarium, with the exception of a lucky few such as clown fish. And, unless you take immediate action, there is a strong possibility that your fish will not survive.

If your tank has shown signs of dinoflagellates and your fish suddenly start getting white spots on their body, I would strongly consider Marine Velvet as the cause.

TREATMENT: Chloroquine phosphate, fresh water dips

As with any disease in a saltwater tank, swift detection and treatment will greatly improve the chances of survival.

Chromis Not Eating

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