Q. I am interested in purchasing two fishes for my reef aquarium. First, I really would like to get a very small queen angelfish. The problem is juvenile queens look almost identical to juvenile blue angels. Can you please give me some hints on making sure that I am actually getting a queen angel instead of a blue?
My second question is about copperband butterflyfish. I noticed in an article that this fish is not terribly destructive in a reef aquarium. And in some cases it is good because it eats glass anemones. But, will a copperband also eat the good anemones that my anemonefish lives in?
A. Before I answer your question, I must discourage you from placing a queen (Holacanthus ciliaris) or blue (H. bermudensis) angelfish in a reef aquarium. Juveniles feed on a variety of encrusting invertebrates and algae, and although you probably will not mind if they eat your plant life, you may not like it if they start nipping at your desirable invertebrates. Sooner or later they will start picking at your corals.
The other problem with both of these fish is that they are aggressive. So, if you want to keep more docile species that are actually better suited to the reef aquarium — such as anthias, comets, assessors, gobies, fire gobies and small wrasses — don’t include these angels. They also get large and need lots of room to move. This is a problem unless you have a huge reef aquarium with plenty of open areas.
Now, regarding your first question. The differences between a “pure-bred” juvenile queen and blue angelfish are quite conspicuous. The problem is, there are also some “mutts” out there because these two species interbreed and produce a hybrid — once known as the Townsend’s angelfish (Holacanthus townsendi) — that can have characteristics similar to either parent, or a mixture of both.
The easiest way to separate these two species is to examine the third blue line from the head, which is positioned near the middle of the dorsal fin. In the queen angel this line is curved toward the tail, whereas in the blue angel it is straight. In juvenile hybrids this line may be curved to varying degrees, making identification dubious. Juvenile queens also tend to be more brightly colored than blues.
As far as your copperband butterflyfish (Chelmon rostratus) is concerned, I have never seen one bother any anemones, except Aiptasia (glass anemones), but when it comes to predicting fish behavior there are always exceptions to the rule. For example, copperbands usually do not bother corals, but I had a customer whose copperband loved to eat her brain corals.
Therefore, it is a good idea to watch this fish very closely when you place it in your reef aquarium to make sure it dose not bother your corals or anemones. If it begins picking on these invertebrates you will have no choice but to remove it.
Although no data exists on the food habits of the copperband in the wild, the yellow longnose butterflyfish (Forcipiger flavissimus), which has a similar jaw morphology, feeds on hydroids, crustaceans, sea urchin tube feet and pedicillaria and tubeworm tentacles. It is safe to surmise that anemones are not on the copperband’s bill of fare in the wild either. In the aquarium, copperbands will regularly eat small fan and Christmas tree worms and small glass anemones, which are all similar in size and appearance.
Another thing your anemone has going in its favor is the resident anemonefish. These fish viciously protect their hosts from anemone predators. So, if your copperband does try and nip your anemone, the anemonefish will chase it off.