There are numerous species of small oval fish that are known for their beauty and colorful patterns. These fish are commonly found in the protected regions of the inner reef, where they form their habitats and are a part of the coral food web, together with corals, anemones, sponges and other species of fish. The clownfish (Amphiprioninae), damselfish (Pomacentridae) and Chromis are among the most well-known varieties of small oval fishes, most of them being found in tropical regions and associated with some intriguing mating and feeding patterns.
Small oval fish are abundant all throughout the world’s oceans, commonly known to thrive in the coastal areas of tropical islands, as well as in bays, lagoons and inner reefs – generally protected habitats where coral reefs and anemones can thrive as well. Although some species, like the oval and melon butterflyfish, are found mainly in specific regions in the Indian Ocean and the Red Sea, there are numerous small oval fish species that live in many different parts of the world. Damselfish species live on tropical coral formations, but can also be found in temperate climates on the coast of Mexico or California. Anemonefish, or clownfish, on the other hand, have a more peculiar lifestyle, living in close symbiotic communion with anemones, most species being quite widespread. They are found in the lagoons and shallow reef formations of the Pacific and Indian Oceans.
Damselfish, anemonefish and chromis are all closely related. In fact, they are known for being part of the Pomacentridae family, which is commonly characterized by various species of damselfish. These fish species are generally small – chromis and anemonefish rarely growing larger than 18-20 cm, while some species of damselfish reaching 35 cm in length – and feature genera and subspecies that comprise up to 400 different individual species of fish known so far. About 360 subspecies are associated with damselfish, featuring superb, colorful fish like the Yellowfin Demoiselle and Rolands Demoiselle, as well as beautiful striped species like the Black-tailed Dascyllus and Honeyhead Damsel.
Small oval fishes, and damselfish in particular, are mainly foragers. They spend roughly 85% of their time during the day foraging and feeding primarily on copepods and caridea species. When currents are low, they may also feed on plankton searching for water columns with a more intense flux. Anemonefish have a more distinctive and quite fascinating feeding pattern, mostly feeding on zooplankton, but also largely depending on anemones for their food. In fact, they may feed both on the leftovers and fecal matter left over by the anemone that they inhabit. Chromis have more diverse eating habits, feeding on cladocera, copepods, zooplankton, and even fish eggs and fish larvae.
Most species of damselfish and quite a few species of other small oval fish are quite territorial, defending their eggs intently until they hatch. Courtship and mating can be quite a complex ritual in the case of most small fish, damselfish males being known to use complex movements like the “signal jump” and courting several females at the same time. Anemonefish follow a similar mating pattern, living in small groups of several males with only one female. A curious fact about these fish is that, in case the female dies or disappears, the strongest male in the group simply turns into a female to ensure the group’s survival.