Arapaima Evolution

The arapaima is a large freshwater fish that lives in the Amazon River. As the arapaima’s habitat disappears due to rising sea levels flooding the Amazon Basin and turning it from fresh to salt water, it will grow smaller. Currently, it grows up to 10 feet long, but it will evolve to be smaller. It will also develop stronger, larger fins that will allow it to be more mobile as its habitat disappears and as it may need to move more to hunt. Currently, the arapaima can live up to 20 years and only reaches sexual maturity after five years of growth, but it will have a shorter lifespan. Due to this, its scales will grow larger and softer so that it can grow faster. It will also have larger proportional gills and lower-set eyes as its prey changes habitat.