ANEMONEFISH FACTS, BY THE NUMBERS
1 All clownfishes are anemonefishes but only two species of anemonefishes get to be called clownfishes, and one of them is the false clownfish (Amphiprion ocellaris).
2 Widely thought of as the archetypal clownfish, the adorable hero of Finding Nemo is actually a false clownfish, with three broad white bands encircling his body. But that’s a design that’s easily animated and he had great marketing reps.
3 The color patterns of true clown anemonefishes (Amphiprion percula) are more harlequinesque. They augment their orange and white with black motifs, sometimes extensive.
4 They’re anemonefishes because they live in mutualistic relationships with sea anemones, finding protection from predators in the anemones’ multitudinous tentacles. At the same time, they give back by consuming parasites and by swimming their way through and around the tentacles, fanning or aerating the waters they all exist in.
MORE ANEMONEFISH FACTS
5 Sometime they prune their hosts by eating dead or diseased tentacles. Another anemonefish fact: They provide nutrients to their sea anemones in the form of fecal matter, otherwise known as fish poop.
6 Key among anemonefish facts: Clownfishes or not, most species are orange. They may be all orange, or orange with black fins, or with thin white cheek stripes, or a white stripe along their backs, or darker patches on their bodies, or some combination of them all. Or, maybe, something else. After all, there are some 30 of them, species-wise.
7 A few species tend towards dark colors. The colors of at least one, Clark’s anemonefish (A. clarkii), can be dark or orange, depending on the color of its host sea anemone.
8 Regardless of their species, all anemonefishes basically earn their livings in the same way. Besides hiding out among sea anemone tentacles, they dine primarily on zooplankton and live in small groups each dominated by a single female.
9 They’re found in the Indo/Pacific basin, from the South Pacific to Mozambique. There are no anemonefish native to the Atlantic/Caribbean regions.
SEA ANEMONE FACTS
10 Unlike their coral polyp relatives, sea anemones don’t build calcium-carbonate walls to hide behind. They’re a lot bigger. And they have a lot more tentacles than coral polyps’ six or eight. But their tentacles do bear the stinging nematocysts that coral tentacles utilize to capture planktonic prey.
11 Anemonefish dine mainly on zooplankton like tiny copepods and tunicate larvae. For green vegetables, they sometimes add algae to their diet. And, they feed on uneaten prey left by their anemone hosts
12 Living in an thicket of stinging tentacles does subject the little guys to the possibility of chronic injury. They deal with this by developing a protective mucous covering. In joining their communities, they acclimate themselves by swimming around their anemone and rubbing their fins and lower bodies on their tentacles.
13 Anemonefish are very anemone-specific. Different species of anemonefish tend to cohabit with specific types of anemones, mostly among some 10 species. And once there, they’ll spend their entire lives in and around that anemone.
14 Most anemonefish communities consist of only a handful of fishes. Each is dominated by a single female – always the largest fish in the group. The second-largest is the male, followed by non-breeding males whose place in the societal group reflects their decreasing sizes.
15 Only the female and the largest male mate (and do so for life), laying eggs in nests on a hard surface, hopefully close enough to the anemone to keep them safe from predators. Sad anemonefish facts are that the fishes themselves find protection in the sea anemones but their egg nests are vulnerable to raids by wrasses and other damselfish.
16 All the other fishes in the little community are males because anemonefish are protandrous hermaphrodites – they all develop as males initially. If the female honcho should exit the scene, her mate (the largest male in the social group) is duty-bound to transform into the dominant female. The next largest male moves up to take up husbandry duties.
17 Those of you who are fans of Finding Nemo may detect a divergence from reality here.
AN ARRAY OF ANEMONEFISHES
REPRODUCTION & LIFE CYCLE–
18 Anemonefish males both prepares the nest and guards and fans the eggs to aerate until they hatch, usually in six to 10 days. A nest may contain up to 1,000 eggs, all of them (naturally) orange.
19 If they have timed their mating correctly, the hatching will correlate with tidal currents, sweeping the anemonefish larvae safely away. After drifting and developing, surviving juveniles follow chemical cues to find and join an anemonefish community.
20 Final anemonefish facts: Each little fish that joins a sea anemone community comes from somewhere else. In anemonefish lives, there are no Mom and Dad relationships involved.
PRINCIPAL SOURCES: Coral Reef Animals of the Indo-Pacific, Terrence Gosliner, David Behrens, Gary Williams; Reef Fish Identification, Tropical Pacific, Gerald Allen, Roger Steene, Paul Humann, Ned DeLoach; Indo-Pacific Coral Reef Field Guide, Gerald Allen, Roger Steene; “Clown Anemonefish,” Florida Museum of Natural History, University of Florida; “Amphiprion ocellaris, Clown anemonefish,” “Amphiprion perideraion Pink anemonefish,” Animal Diversity Web, University of Michigan; “Amphiprionae,” “Sea Anemone,” Wikipedia. Wikipedia Commons images used under public sharing licenses.