You have a problem in your reef tank. Ugly brown anemones called Aiptasia are growing everywhere, stinging your corals.
You go to the forum, and everyone says: “Get a Copperband Butterfly. They eat Aiptasia.”
You go to the shop. You see the Copperband Butterflyfish (Chelmon rostratus). It is silver with stunning orange vertical bands and a long, delicate beak. It looks like a piece of fine china. You buy it.
Two weeks later, your Aiptasia is gone, but your beautiful fish is dead.
This is the sad reality for 80% of Copperbands. They are not just pest controllers; they are delicate experts. Here is how to keep one alive.
1. The “Beak” Design
The Copperband has a long, tweezer-like mouth. In the wild, it uses this to pick tiny worms and crustaceans out of deep rock crevices.
- The Problem: It cannot eat normal food. Floating pellets move too fast. Large chunks of shrimp are too big.
- The Result: If you just throw pellets in the tank, the fish will ignore them and starve.
2. The “Aiptasia” Gamble
Yes, they eat Aiptasia (pest anemones). They are the best biological control in the world for this.
- The Catch: Once they eat all the Aiptasia… what’s next?
- Many Copperbands are “specialists.” They will eat all the pests in your tank in 3 days, and then refuse to eat anything else. You literally run out of food for them.
3. The “Wet Market” Hack (How to Save Them)
In Malaysia, we have a secret weapon that Americans don’t have: Fresh Cockles (Kerang).
This is the #1 way to get a Copperband to eat.
- The Method: Buy fresh Kerang from the Pasar Pagi. Scrub the shell clean. Crack it open slightly (or freeze it and open it). Drop the whole shell into the tank.
- Why it works: The Copperband recognizes the shell. It uses its long beak to pick the meat out. This mimics its natural hunting behavior.
- Transition: Once it is eating clams, you can start stuffing the empty shells with frozen Mysis shrimp to trick it into eating frozen food.
4. The “Bully” Magnet
Copperbands are incredibly shy and gentle.
If you have aggressive fish like Tangs or Damsels, they will attack the Copperband.
- The Stress: Because the Copperband is a slow eater, fast fish will steal all the food before the Copperband decides to take a bite. It will eventually die of stress and malnutrition.
- The Rule: Only keep them in peaceful tanks or introduce them first, before the aggressive fish.
5. Are They Reef Safe?
Mostly, yes.
They generally leave stony corals (SPS/LPS) alone. However, they might pick at:
- Feather Duster Worms (Coco Worms).
- Clams (Tridacna).
- Acanthastrea (sometimes).
The Copperband Butterfly is one of the most elegant fish in the ocean. But it is not a “starter fish.”
Do not buy it just to clean your pests. Only buy it if you are willing to visit the wet market to buy fresh clams and spend time training it to eat.
