Green chromis care

Quick reference

What is a green chromis?

Chromis viridis ranges across the Indo-Pacific, from East Africa to the Line Islands and the Tuamotus, at 1–20 m.^[3] Adults gather in large aggregations above thickets of branching Acropora in sheltered reef flats and lagoons, and FishBase describes them as plankton feeders.^[3] Males prepare a nest that several females spawn in, then guard and fan the eggs.^[3]

Feeding

LiveAquaria recommends meaty foods, herbivore flakes and frozen preparations, fed several times throughout the day.^[1] In the wild they pick plankton from the water column,^[3] so small, frequent feedings suit them better than one big one.^[1]

Aggression and spacing

LiveAquaria calls it peaceful for a damselfish and says it can live with almost all community fish, invertebrates and corals.^[1] Within a group it's another story. WetWebMedia's crew say chromis tend to fight among themselves and can be territorial toward newcomers, and advise adding three to five at once, in odd numbers, since a single new fish added to an established group is often picked on.^[2] Plan for the group to shrink over time.^[2]

Tankmates

Reef compatible with corals and invertebrates.^[1] Keep rockwork low enough to leave open water: WetWebMedia notes chromis school more naturally with open swimming room in larger systems.^[2]

Disease and quarantine

We found no disease information specific to the green chromis. General marine fish guidance applies: CORAL Magazine recommends quarantining every incoming fish, captive-bred included, for at least 2–4 weeks, and UF/IFAS advises 3–6 weeks at 24–27 °C, longer when ich is suspected.^{[4, 5]} A WetWebMedia crew member noted high mortality in shipments and advised buying small, healthy fish from a good source, quarantining them, and acclimating slowly.^[2]

Breeding

In the wild, males prepare a nest shared with several females and guard and aerate the eggs.^[3] We found no reliable report of commercial captive breeding.

Troubleshooting

Common mistakes

• •Expecting a group to stay a peaceful school forever.^[2]
• •Adding chromis one at a time to an existing group.^[2]
• •Too many for the tank.^[2]
• •Skipping quarantine.^{[2, 4]}

Equipment & food for this species

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Frozen mysis is a good staple and quality pellets cover daily feeding. Many keepers soak food in a vitamin supplement such as Selcon.

Green chromis FAQ

How many green chromis should I get?

LiveAquaria suggests a school of at least six;^[1] WetWebMedia's crew suggest adding three to five at once, in odd numbers.^[2]

Why do my chromis keep dying?

Commonly fighting within the group, aimed at the newest or weakest fish, and shipping stress or disease.^[2] Add them together and quarantine them.^{[2, 4]}

Are green chromis reef safe?

Yes. LiveAquaria lists it as reef compatible.^[1]

What size tank do green chromis need?

LiveAquaria says 30 gallons; for a group, we use 55.^{[1, 2]}

Are green chromis aggressive?

Peaceful toward other species,^[1] but they can fight among themselves and pick on newcomers.^[2]

How big do green chromis get?

Up to 10 cm (4 in).^{[3, 1]}