Good Things to Know About Fish & Reefs
The serranids make up a very large family of fish, many of which are offered for aquariums. These fish range from quite small to very large. The larger members, which include the groupers or rock cods, soapfish and basses, are quite predatory and cannot be kept with smaller fish. Even smaller serranids, anthias, roundheads and dottybacks, should generally not be kept with bite-sized tank mates, keeping them with fish of a similar or larger size is recommended. Some members, particularly the dottybacks, can be quite territorial and aggressive to others of their own or similar species. However, in contrast, anthias form schools (but with one male only in the company of a harem of females).
Groupers and rock cods are large predatory fish. Some grow enormous, eg the potato cod, grows to over 2m long, but most of the species offered for aquariums grow to a more moderate (but still considerable) 40 to 60cm, with some even smaller. They are hardy fish and tolerate a range of water quality but produce copious waste so good filtration is needed. They will regard any fish or invertebrates small enough to be swallowed as food, and due to their messy habits, they are not recommended for coral/anemone tanks. They appreciate darkened hideaways and will often spend time apparently "sulking", resting or hiding away, but once settled can become quite tame and will become more active and outgoing. Be aware that they may dig and re-arrange tank decor. Species that are sometimes available include the flag tail rockcod (Cephalopholis urodeta) which grows to 27cm, the blue-spotted rockcod (Cephalopholis cyanostigma, 35cm), and the polkadot grouper (Chromileptes altivelis, 70cm).
Showy and predatory fish, but not overly aggressive. They have large mouths, so take care to get tankmates of a suitably large size. Lionfish are very hardy and become very tame. Common sense and care should be taken when cleaning their aquarium. Their spines are venomous - not lethally so except where allergies exist, but the sting is very painful! However, the spines are a defensive measure, and a careful aquarist should never be stung.
These small to medium sized, brightly colored fish are amongst the hardiest and most popular species. They are a good starter fish as they are amongst the toughest marine fish and also amongst the cheapest. The main drawback of damsels is that most are territorial and some can be quite aggressive. However, most can be kept with other fish so long as adequate space and territory is provided, and some are far less territorial than others. Probably the most placid damsels are the chromis (Chromis species), which will even school together. In general, Chrysiptera species are less aggressive than Dascyllus, which in turn are less aggressive than Pomacentrus and Abudefduf species. All types are reef safe.
Types that are available fairly commonly include the green chromis (Chromis viridis), Humbugs (Dascyllus auranus), Dominos (D. trimaculatus) and blue damsels (Pomacentrus pavo). Also available from time to time are Barrier reef chromis (Chromis nitida), Fiji damsels (Chrysiptera tapou), Orange-tail blue damsels (C. cyanea), Talbot damsels (C. talboti), Reticulate damsels (Dascyllus reticulatus), Neon damsels (Pomacentrus coelestis), Yellow damsels (P. mollucensis) and Sargent majors (Abudefduf sexfasciatus).
One of the best known of all salt water fish and one of the most popular, Clownfish are one of the hardiest marine fish and quite easy to keep. Small specimens mix with most other fish but larger specimens may be quite territorial, especially towards each other and towards other clownfish. If you wish to keep several clowns together, it is best to choose types that will all reach a similar adult size and to acquire them all at a small size and let them grow up together. Clownfish are not born with a determined sex, when they pair up, the dominant fish becomes female, and often grows larger. If the female dies, the male can transform to become female. Clownfish have been bred in captivity and tank-bred specimens of a number of species are becoming available more and more frequently.
All clownfish are reef friendly. In the wild they are known for their relationship with sea anemones. Unlike most other fish, clownfish are able to swim amongst the anemone tentacles and not be stung and they use the anemones for shelter. Different clownfish species associate with different types of anemones. Some use a number of species, while others will use only one type. However, in the aquarium, clownfish do not require an anemone. Even where one of a suitable type is provided, they tend to use it far less frequently than they would in the wild, quite possibly because they do not need the shelter since the aquarium is generally free from predators. In a reef tank it is often worthwhile providing an anemone as when it is used the behavior is fascinating to watch. Clownfish will sometimes use corals as well, and occasionally a coral may be disturbed by this. If this happens, this is one time where an anemone should be introduced to prevent harm to the coral. In a fish-only tank it is generally not recommended to add an anemone. Anemones have very specific requirements to thrive and these are difficult to provide in a set up that is dedicated primarily to fish.
The so called "common" clowns or clown anemone fish Amphiprion ocellaris & percula are easily the most recognized clownfish, but are actually not the most common species in Australian waters. These two species look virtually identical and can only be reliably distinguished by fin ray counts, or by knowing where they were caught since the two species occur in different areas. Telling them apart is rarely important though as their care and requirements are also identical. Both are now being captive bred in Australia. In the wild by far the most common species is the brown or Barrier reef clown A. akyndinos. Also available both wild-caught and occasionally captive bred are tomato clowns (A. melanopus), the orange finned clown (A. clarkii), the pink skunk clown (A. periadion) and the maroon clown (Premnas biaculeatus).
Angelfish are some of the most popular marine fish, although some can be expensive, most are brightly colored and many are quite hardy. As with many other groups of fish survival of angelfish is strongly influenced by how they are collected. Net caught fish demand a much higher price than drug caught, but the long-term survival rate of drug-caught fish is nil, so the investment in net caught fish is worthwhile! A few angelfish have been spawned and raised in captivity but as yet none are being bred commercially.
Angels can be divided into three groups. Firstly there are the dwarf angels of the genus Centropyge. These grow (depending on species) to between 6cm and 15cm and are some of the most popular aquarium fish. They can be aggressive towards others of their own species or very similar species but are rarely aggressive towards any other kind of fish. While some individuals occasionally pick at corals, most are considered relatively reef-friendly. Their diet in the wild consists largely of algae, supplemented with small invertebrates. Most are quite hardy, but they can be sensitive to high nitrate levels. Available types include the bicolor (C. bicolor), coral beauty (C. bisponosa), heraldi (C. heraldi), less often the keyhole (C. tibicen) and pearlscale (C. vrolikii), which are a little more demanding, and rarely the flame angelfish (C. loricula). Unfortunately this latter fish is often imported in Australia from areas where drug-catching is still rife, and finding good quality specimens is difficult.
The second group is of mid-sized angelfish including Genicanthus, Apolemichthys, Chaetodontoplus and Pygoplites species. These species are between 15cm and 30cm in size and not kept as commonly in aquariums. The Genicanthus species are similar in their requirements and temperament to dwarf angelfish, but are generally more expensive and not as brightly colored. They are the smallest of the mid-sized angels but are active swimmers that need plenty of room. Like the dwarf angels, they may sometime spick at corals but are often successfully kept in reef tanks. Most commonly available in this genus are the blackspot angel (G. melanospilus) and Watanabe angel (G. watanabei). In general Apolemichthys and Chaetodontoplus species are more delicate, but in a well set-up and established system they can certainly be kept. In this group the three-spot angelfish (A. trimaculatus), yellowtail angelfish (C. meredithii) and scribbled angelfish (C. duboulayi) are most often seen. The regal angelfish (P. diacanthus) is the only member of the genus Pygoplites. This is a very demanding fish, suitable only for very experienced hobbyists.
Finally there are the large angelfish: Pomacanthus and Holocanthus species, although only members of the Pomacanthus occur in Australian waters. These fish grow to between 20 and 50cm with Pomacanthus species typically between 30 and 40cm in length as adults. Pomacanthus species have a juvenile stage which is very different from the adult coloration: typically a deep blue base covered with oval, semicircular or scribbled lines of white and light blue. The juveniles of most species look similar but can be distinguished by their slightly different patterns of lines. These fish are all coral and invertebrate eaters that will decimate a reef tank. Fortunately most do adapt to other foods and can be kept in fish-only tanks. While they do not do well in new tanks, in established systems the majority of these large angels can be kept successfully. They are territorial, especially towards other angels, although individuals of different species and similar size may co-habit in large enough aquaria if introduced at the same time. Large angels should not be mixed with small or shy fish. Available types that are relatively hardy include the Emperor angelfish (P. imperator), Koran or Semicircle angelfish (P. semicircularis) and the sixbar angelfish (P. sexstriatus). Also available from time to time is the more demanding blueface angel (P. xanthometapon) which does not always take to feeding in the aquarium.