By Scott W. Michael
Q. I am interested in buying a fish that I saw at a local aquarium store — a clown sweetlips. It is brown with white spots and swims like a clownfish.
A friend of mine, who also has saltwater fish, tells me that he thinks they are difficult to keep, but the shop owner disagrees. I was interested in any information you could give me on its care.
A. The fish you are referring to is the clown or harlequin sweetlips, Plectorhinchus chaetodonoides. This species belongs to the family Haemulidae, which includes other sweetlips and grunts(so named for their ability to produce a grunting noise by grinding their pharyngeal teeth, which is amplified by the swimbladder).
There are nine species in the genus Plectorhinchus, several of which are commonly seen in aquarium stores. The most common is the clown sweetlips. It ranges from islands in the Indian Ocean, east to Samoa, north to southern Japan and south to Australia, and is typically found in waters 3 to 100 feet in depth (Myers 1989). Juveniles, under about 3 inches, are brown overall with black-bordered white spots and white-and-black fins. As they grow they develop brown spots on a white background, which become more numerous as they age. Not only is there a dramatic color change, but there is also a radical transformation in size! Most aquarists do not realize that this species gets big, attaining a maximum length of 24 inches. Therefore, it is important that you have a sizable aquarium (135 gallons or larger) if you hope to raise this fish to adulthood.
Besides appearance, another endearing quality of this fish is its swimming behavior, which is similar to that of a clownfish. Juveniles undulate their bodies and scull with their enlarged pectoral fins when they swim or when they hang in the water column. These exaggerated swimming movements, as well as the juvenile coloration, apparently function to deter would-be predators.
It has been suggested that they look like a noxious, or distasteful, flatworm and are avoided by predators as a result. This type of mimicry — when a nontoxic species resembles a toxic one — is called Batesian mimicry.
Although mimicking a noxious flatworm may help prevent the sweetlips from becoming predator chow, it does not give it immunity from aggressive species in the aquarium. The big wagging tail and waving paired fins of this species are perfect targets for combative tankmates, such as damselfishes, hawkfishes, certain angelfishes, tiggerfishes, pufferfishes and porcupinefishes. Therefore, another prerequisite for maintaining a small clown sweetlips is to house it with passive species.
During the day these fish hide in crevices, under ledges, among branching corals and between or under coral boulders. At night they come out to feed — the adult's diet consisting of mollusks, crustaceans and small fish (Myers 1989). Although no data exists on juvenile food habits, they probably feed on worms and small crustaceans.
Unfortunately, one of the biggest drawbacks to keeping this fish in captivity is getting it to feed. I have had the most success with live ghost or glass shrimp, often sold to freshwater aquarists. These shrimp are euryhaline (able to live in waters of a wide range of salinity) and will survive in full-strength seawater. In order to induce the fish to feed it is best that your clown sweetlips is not kept with aggressive feeders that will also eat these shrimp, such as squirrelfishes, soldierfishes, groupers, snappers, goatfishes, and large wrasses.
Once you induce feeding, food competitors can then be added. You can place the shrimp directly into the aquarium, but if it is packed with decor you may not be able to see if the fish locates and eats them. Try adding the shrimp in a shallow wide-mouthed jar, the opening of which should be big enough to allow the fish easy entry. Set the jar on the bottom of the aquarium with the mouth up. The shrimp will be unable to escape, but the fish will be able to swim in and eat them! Fortunately, as clown sweetlips mature they become less finicky about accepting aquarium fare.
Sometimes these fish will eat for weeks or months and then suddenly cease and die for no apparent reason. This may indicate the fish was captured with drugs (cyanide), the effects of which may not manifest themselves immediately. Death may also be the result of some key nutritional ingredient missing from their diets.
If you have to use glass or brine shrimp to get your sweetlips to feed, it is a good idea to wean them off live food and try and feed them a more varied diet. Soaking frozen or fresh foods in Selcon (a vitamin and fatty acid supplement from American Marine Inc.) before it is fed will also help ensure long-term health.
As mentioned above juveniles are also somewhat reclusive during the day. Therefore, it is important to provide them with good hiding places to reduce stress levels.
In conclusion, I would have to agree with your friend: This is a sensitive fish that is not easy to maintain. Thus, I would recommend that you avoid this fish unless you are willing to meet the specific needs prescribed above.
Avoid the Queen
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. 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? Any help you can provide is much appreciated.
A. Before I answer your question, I will 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, which 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 "purebred" 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 (Hobson 1974).
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.