Chromis
Chromis are damsels that shoal, and they are the cheapest way to get movement into a marine tank. Gallery Aquatica stocks three species at our shop in Tingalpa, east of the Brisbane CBD.
Chromis are in-store purchase and pickup only. We do not send live fish by courier or freight. Ring 0420 484 584 to check what is in.
Read this before you buy six
Chromis are sold on the promise of a shimmering shoal, and it is worth knowing up front that a home aquarium usually does not deliver one.
On the reef, chromis shoal in the hundreds and aggression disperses harmlessly across the group. In a tank of six, it concentrates. What typically happens is that over the first few months the group establishes a hierarchy, the dominant fish singles out the weakest, and the group reduces itself - often down to two or three, sometimes to one. This is normal behaviour, not a disease and not your water quality.
You can improve the odds. Buy more rather than fewer - nine holds together better than five, because there are more targets to spread the pressure. Give them a bigger tank than the minimum. Make sure there is plenty of rockwork so a harassed fish can break line of sight. And buy them all at once, the same size, rather than adding to an established group.
None of that guarantees a lasting shoal. If a permanent group of small fish is what you want, a shoal of zebra dartfish or a group of anthias holds together more reliably - the anthias needing considerably more feeding in exchange.
What chromis do offer, honestly stated: they are the hardiest and cheapest marine fish available, they eat anything, they tolerate the swings of a young tank better than almost anything else, and even two or three of them put constant movement in the upper water. For a first marine tank that is a sensible place to start.
The chromis we stock
Blue Green Chromis (Chromis viridis)
The standard, and one of the most widely sold marine fish in the world. Iridescent blue-green over a pale belly, catching the light as it turns. Reaches 8 cm and works in 110 litres.
Cheap, hardy and completely undemanding. It will take flake, pellet and frozen food without hesitation, and it copes with the parameter swings of a newly established tank better than anything else we sell. Buy five or more, ideally more. Reef safe.
Vanderbilt's Chromis (Chromis vanderbilti, listed as Van Der Bilts)
The smallest chromis here at 6 cm, comfortable in 110 litres. Slim-bodied, with fine horizontal blue and yellow lining along a darker back - a subtler fish than the blue green and better looking close up.
It also holds a tighter shoal than Chromis viridis does, which given the section above is a real advantage. Less commonly available, so worth asking about. Reef safe.
Other chromis we regularly stock
Also part of our regular range. Ask us in store or ring 0420 484 584 for size and details.
- Great Barrier Reef Chromis
Which chromis should you buy?
Blue green chromis for a first marine tank - cheapest, hardiest, most available. Buy at least five, and more if the tank allows.
Vanderbilt's if you want the better-looking fish and the more reliable shoal, and can find them in stock.
Whichever you choose, one species per tank. Mixed chromis species do not shoal together and simply give each other something extra to fight about.
Tankmates
Chromis get on with nearly everything peaceful: clownfish, gobies, blennies, tangs, anthias, Banggai cardinals and dwarf angelfish.
A midas blenny will often join a chromis shoal and swim as part of it, which is worth setting up deliberately.
At 6 to 10 cm, chromis are exactly the size that predators eat. Keep them away from lionfish, morays, triggerfish and large angelfish.
Common questions
Do you ship chromis?
No. All marine fish are in-store purchase and pickup only. We do not send live fish by courier or freight.
Are these chromis in stock right now?
These are the species we stock as our regular range, not a live inventory. Ring 0420 484 584 or email shop@galleryaquatica.com.au to check.
How many chromis should I buy?
More than you think - five at minimum and nine or more if the tank allows. Larger groups spread aggression across more fish and hold together better. Buy them all at once and at the same size rather than adding to an established group.
Why are my chromis killing each other?
Because that is what they do in a tank. On the reef, shoals number in the hundreds and aggression disperses. In a group of six it concentrates on the weakest fish, and groups commonly reduce themselves to two or three over the first few months. It is normal behaviour rather than illness. More fish, more rockwork and a bigger tank all help.
Are chromis good for a first marine tank?
Yes, with the caveat above. They are the hardiest and cheapest marine fish available, they eat anything offered, and they tolerate the instability of a young tank well. Expect the group to shrink.
What size tank do chromis need?
A blue green or Vanderbilt's works in around 110 litres. Bear in mind you want a group, so err on the larger side - more space reduces the aggression that breaks up a shoal.
Are chromis reef safe?
Yes. They feed on plankton and prepared food in open water and take no interest in coral or invertebrates.
Can I mix different chromis species?
Better not to. Different species will not shoal together, so you gain nothing and add another source of aggression. One species per tank.
More marine fish
See all the marine fish we stock, or the Brisbane store page for coral and equipment.