#wallum

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CLICK HERE FOR THE AC FISH EXPLAINED MASTERPOST

Jeez, sorry, I know I haven’t done one of these in a while, and with that, I’ve awkwardly missed some creatures that left after September or October...so let’s go over them, shall we? Today’s fish, the Rainbowfish, is a really cool little fish that left us in the Northern Hemisphere yesterday, so, if you didn’t get it, better luck in May...or time traveling, I’m not here to judge.

The name ‘rainbowfish’ actually refers to a whole Family of fish, the Melanotaeniidae. They are in the Order Atheriniformes, the silversides, which are typically boring old silver, with the rainbowfish being the striking exceptions. They’re all pretty tiny fish, though, so you can imagine that they have a lot of predators, like other, bigger fish, birds, etc. Rainbowfish are really popular aquarium fish - they’re typically easy to care for because they will eat flake food easily and are known to be calm, community fish. Even so, many species of rainbowfish are endangered in the wild because their wetland and river habitats are constantly threatened by human development. We’ve talked about that before, that freshwater and coastal fish got it rough because of how closely they live to humans and how we like to use rivers as dumps. It’s sad, really.

ACNH’s rainbowfish is most definitely the Ornate Rainbowfish, (Rhadinocentrus ornatus), a more narrow-bodied fish than the other fish in its Family. 

The Ornate Rainbow is actually really interesting because it’s endemic to a very specific habitat called a Wallum Ecosystem, which is a very special, shrubby wetland in eastern Australia. The ecosystem is characterized by the wallum banksia, a kind of shrub that grows in sandy, acidic soil. The area is known to have frequent wildfires as well as seasonal flooding. The streams in the area each have their own, genetically distinct population of Ornate Rainbow, each of which has different patterns and colors. The one in ACNH is most likely from the population of Seary’s Creek by Tin Can Bay, Australia, pictured above. To give you an idea of how restricted an area we are talking about, here’s a map of Australia with the Ornate’s range, which is almost exactly the range of “Wallum Country”, shaded in red:

This is one of those areas that ought to be protected, as it isn’t just the Ornate Rainbow that’s endemic to this ecosystem. A number of frogs and birds call only this place home. Once it’s gone for yet another marina, neighborhood, or what have you, they are all gone.