Clownfish – a showcase of coral reefs in the aquarium
Clownfish are an iconic group of fish in the world of reef tanks, further popularized by the movie Finding Nemo. There are over a dozen species of clownfish, each varying in coloration, patterns, and shape. In recent years, aquarists have also introduced hybrid varieties, featuring unique combinations of patterns and colors. A distinguishing feature of clownfish is their symbiotic relationship with anemones, which can be replicated under aquarium conditions.
Systematics
Clownfish belong to the family Pomacentridae, alongside damselfish (Pomacentrinae) and chromis (Chrominae). Among the most popular clownfish species in aquariums are Amphiprion ocellaris and Amphiprion percula. With the introduction of various hybrids and color morphs in the trade, names like “Picasso” and “Snowflake” have become common. Other species found in the aquarium hobby include Premnas biaculeatus, Premnas epigrammata, Amphiprion frenatus, and Amphiprion perideraion.
Characteristics
Captive-bred fish typically grow no larger than 5 cm, although wild specimens reaching up to 10 cm are also available. They are not strong swimmers and tend to stay close to their nest or anemone. In the wild, clownfish rely heavily on anemones for protection, but in an aquarium, they can adapt to life without one. Sometimes, they choose other corals as substitutes for anemones, often preferring LPS corals like those from the Euphyllia genus or soft corals such as Sarcophyton.
These fish are generally peaceful, though they become territorial when guarding their eggs. In such cases, they may exhibit defensive behaviors to deter intruders. However, they often show aggression toward unfamiliar clownfish pairs, especially those without their own nesting site. Imported specimens can sometimes surprise aquarists by attacking their hands during maintenance—an unexpected and occasionally painful behavior.
Sexual dimorphism
Clownfish are sequential hermaphrodites, meaning they are born with both male and female reproductive organs. They initially develop as males, but in the absence of a female, the largest male in the group transforms into an alpha female, while the second-largest becomes the alpha male. If you purchase two sexually immature fish, one will eventually develop into a male and the other into a female.
Aquarium requirements
In my opinion, the absolute minimum tank size for a pair of clownfish and an anemone is 50 liters. However, the beauty of such a setup truly shines in a larger tank, especially if the anemone hosts two pairs of fish—a rare but possible occurrence.
What Do Clownfish Eat?
Clownfish are not fussy eaters. They readily accept Tropical Marine Power Oceanic Mix flakes and, with a bit of patience, smaller pellets from the Marine Power line, especially the dedicated Tropical Marine Power Clownfish food. Interestingly, clownfish have been observed actively feeding their host anemones by spitting previously caught food into them.
Overall, all fish in the Pomacentridae family are relatively easy to maintain and serve primarily as decorative additions to the aquarium. They pose no threat to invertebrates in the tank.
Bartek Stańczyk
