For colour, beauty and sheer drama, there’s nothing quite like a tang.
Here’s a riot of colour for your reef tank – come to the tang party and meet the bestdressed guests in town.
If there is a group of fish that aquarists consider to be compulsory additions to the marine aquarium, it’s the members of the family Acanthuridae. We know them collectively as tangs but they also go by the name surgeonfish or, for at least one genus, Unicornfish.
tangs are not only beautiful, they have the potential to be highly useful in many aquaria. What could be better than fish that not only look amazing, but also earn their keep?
the Acanthuridae family contains more than 80 species belonging to six genera. five of these – Acanthurus, Ctenochaetus, Naso, Paracanthurus and Zebrasoma – have species that are commonly available in the hobby.
tangs and surgeonfish get their common name from the specialised scales located on the caudal peduncle that can inflict serious wounds due to their scalpel-like sharpness. these are used to threaten rivals, deployed in a defensive role, or used to deter other species from entering territories.
the spines of some species, such as the regal tang, Paracanthurus hepatus, have been shown to be mildly venomous, but not all Acanthurids have been investigated and many are certainly not.
Diet & feeding
Most tang species are herbivorous, feeding on algae including macro, filamentous, calcareous, diatomaceous and even blue-green forms. Some are rather specific in the alga they consume, whereas others are more generalised herbivores. One genus, Ctenochaetus, the bristletooth tangs, have brush-like teeth that have evolved to effectively remove detritus and algal films from hard surfaces.
Providing a diet of sufficient quality and quantity to reverse weight loss is essential during the important early days and weeks of aquarium life for a newly imported fish. tangs often arrive looking very skinny and normal reef aquarium rations may not be sufficient. So the onus is on the aquarist to ensure the fish concerned receives enough calories not only to sustain it, but also to allow it to recover lost body mass
fortunately, for most species the provision of both particulate diets such as frozen brineshrimp and Mysis and dried seaweed on clips can allow these fish to gain weight quickly and keep it on.
for the most part, tangs are considered reef safe, particularly when they are well fed.
rogues occur, however. I have experienced a regal tang that actively consumed zoanthids and clam mantles, but such cases are rare. Usually, tangs are a positive influence in coral-rich aquaria because they perform a useful role in the prevention and control of nuisance algae.
Many Acanthurids suffer greatly when infested with protozoan parasites such as marine velvet (Amyloodinium) and marine white spot (Cryptocaryon).
Although certain species seem particularly resistant to such infections, there are others for whom an outbreak should be expected – it might take days or weeks, but it’s coming. For species such as the Regal tang, P. hepatus, Yellow-eyed tang, C. strigosus, and the Powder blue tang, Acanthurus leucosternon, precautions should ideally be taken before introduction.
For me, UV sterilisers are essential for these species – perhaps for all tangs – as they help to lower the overall numbers of parasites and algae at the free-floating stage of their life cycle. Quarantining is useful, but having something working for you in the display tank is just as important in my opinion.
Tangs are territorial. Some tangs are very territorial. Simultaneous introductions help to reduce territorial aggression between species that are likely to clash, though some species will dominate an aquarium eventually, regardless of how diminutive and apparently timid they appeared when first introduced. Draw up a stocking list and try to add the most territorially aggressive species last.
ABOVE: Different-looking tangs can live together comfortably.
BELOW LEFT: Naturally tangs live in large numbers.
BELOW centre: Indian Ocean or Desjardine tang.
BELOW right: Yellow-eyed kole tangs are detritus eaters.