Damselfishes are an extremely important
group of ubiquitous, circumtropical coral reef fishes. Along
with the clown-anemone fishes (Amphiprion, Premnas)damselfishes
make up the family Pomacentridae, with some 28 genera and @
321 species. We will discuss the anenomefishes (Subfamily
Amphiprionae) in a following article.
Damselfishes (Subfamily Chrominae)
provide a vital link both as reef forage fishes as well as
excellent beginner marine aquarium specimens. Their
extensive use is well-warranted considering their diversity,
beauty and tolerance of chemical and physical conditions,
gregariousness when crowded and general compatibility with
fishes and invertebrates. Most damselfish species accept all
types of food eagerly and are very disease resistant.
The family's taxonomy in currently
poorly known, and a wide open field with species "groups"
blending/grading between different island groups. On the
higher taxonomic plane, pomacentrids are closely related to
cichlids which they resemble in structure, form and behavior.
Both families are in the same Sub-Order of the largest Order
of fishes, the Perciformes. These two families are notable
within the group for being the only two families with only
one pair of nostrils (nares) in most species.
Damselfishes are generally small with
some species, the California garibaldi (Hypsypops
rubicunda) and the giant Cortez damsel (Microspathodon
dorsalis) reaching about a foot in length. Many are
brilliantly hued in blues, greens, violets, reds and browns;
several appear metallic. Quite a few damsels are or become
drab brown or olive in later life and there are sometimes
striking color and structural differences between the sexes.
On any given day a handful or two of
species are readily available from dealers. This mix
generally includes Three-Spots or Dominoes (Dascyllus
trimaculatus, Three and Four Stripes or Humbugs (Dascyllus
aruanus et al.) Yellow-Tail Blue and Blue Damsels (Chromis
cyaneus et al.) various chromis, "Beau" Damsels (Stegastes
spp.), Sargent Majors (Abudefduf species), so-called
"Deep Water" Damsels (Glyphidodontops species et al)
As with many cichlid species, the
following generalities exist when picking out damsels:
1) Buy from reputable dealers;
ones who earn your trust, that feed, care for their stock
and your business.
2) Buy from systems with no dead or
dying specimens. Look for signs of gill burn/ammonia
poisoning from recent shipping; cut-marks on damsels from
mis-handling and aggression, and avoid that tank. Beware of
tanks of damsels with individuals hanging, drifting around
having "private meetings".
3) Don't buy the smallest (less
than 2 cm.) or the largest individuals available. Small
ones die easily and large ones don't adapt well behaviorally
to captive conditions.
4) Buy them all about the same size;
this reduces inter- and intra-species aggression.
5) Buy stock that have
acclimated-stabilized. Damsels that have been adequately
acclimated and held for just a day or two are extremely
hardy; just-new ones may die easily.
Damselfishes are easy to keep in
aquaria; they are not fussy in terms of water chemistry and
physics. Temperatures in the low to upper 70's degree F.
(72-78) are ideal. Most tolerate and enjoy a wide range of
salinities. The industry usually keeps theirs in a specific
gravity of @ 1.017-1.018 to decrease salt mix costs,
increase gas solubility, reduce algae growth and curtail
Any amount of light, dim to bright,
seems OK. Natural or synthetic water makes no difference in
terms of vitality or reproduction in captivity. A pH of 7.5
to 8.3 is favored; no ammonia, nitrite and as low a
concentration of nitrates as practical is the rule as with
Many people take the risk of
introducing pests, parasites & pollution by using a
"floating & mixing" technique, pouring the damsels into
their system. Don't do it! At the very least,
appropriate procedure should involve bringing temperatures
about equal, a freshwater dip with or without formaldehyde
&/or copper & if possible, a two week quarantine.
Damselfishes are a group that are
better to start feeding as soon as possible. Frequent, small
feedings of a variety of foods (dry, frozen, fresh, & live;
both vegetable and animal) will help settle in the stock and
reduce aggressive turmoil.
1) Territoriality may be alleviated by
under-crowding, one or less per 5-10 gallons, and providng
plenty of cover.
2) If possible, buy a batch and
introduce them to a new damsel-free tank all at once. If not
possible/practical to do, move the tank decorations around,
upsetting territories, when introducing new specimens.
3) They like hiding spaces. Provide
coral, shells, plants- some nooks and crannies for
social-psychological shelter. Keep the number and type of
decorations simple to facilitate removal for cleaning, and
possibly netting out livestock.
4) Some damsels, especially when they
get larger and more aggressive, should be displayed with no
other damsels. Examples include neon-velvets, dominos,
hawaiian dascyllus, giant sea of cortez, garibaldis. Keep
your eye on your populations and move those bullies.
Maintaining these with larger angels, tangs, most
triggerfishes, etc. tones them down a peg.
5) Be aware that small damsels are a
dietary mainstay for most fishes whose mouths are large
enough to accommodate them. Measure those lionfishes and
basses before introduction.
Some damsels are specialized
planktivores to herbivores in the wild. In captivity damsels
accept all foods greedily. In fact, sargent-majors are
legend for their use in training other shy species to
Frequent small feedings 2-3 times per
day of a mix of foods sustains them well. Nutritional
diseases are all but unknown in this family.
Infectious and Parasitic Disease:
Damselfishes are parasitized
internally and externally by several species of sporozoans,
Crytocaryon, Oodinium, roundworms, flukes
tapeworms and crustaceans. The presence, abundance and
susceptability of these pathogens to varying salinities and
treatments is complex. Damsels for the most part are disease
resistant and if preventative measures have been executed
and their environment is optimized you can expect low
Most treatable conditions (external)
can be excluded by the freshwater dip treatment and low
specific gravity mentioned before. Damselfishes respond well
to periodic prophylactic copper treatments. Internal "worm"
parasites are sometimes easy to diagnose but difficult to
cure. For internal problems, most preventative and treatment
therapeutics can only be applied via food; injection or bath
for internal parasite control should be avoided for these
fishes as they will probably do more harm than good.
This can be a type of social disease.
Keep your stock under-crowded, and observe them daily for
extreme interactions. Remove all bullies. Inter-specific
aggression is probably the single largest source of
How long do they live? Some damsels
have been kept in captivity for more than ten years and
known to have lived more than twenty in the ocean.
Most damsels reproduce like many
substrate spawners; their behavior is similar to typical
central-American neo-tropical cichlids. Other similarities
with their contrasting freshwater cousins include an
incomplete lateral line, a toothless palate, single,
continuous dorsal fins and territorial behavior.
Major areas of interesting damselfish
biology will not be explored here. Chemical and sound
communication, breeding and other behavior are rich
adventures to be explored in a literature search and in you
the permission of Robert (Bob) Fenner webmaster of WetWebMedia