Sawfish
Sawfish are primarily found in coastal marine and estuarine brackish waters, but they are euryhaline (can adapt to various salinities) and also found in freshwater. The largetooth sawfish, alternatively called the freshwater sawfish, has the greatest affinity for freshwater. For example, it has been reported as far as up the Amazon River and in Lake Nicaragua, and its young spend the first years of their life in freshwater. In contrast, the smalltooth, green and dwarf sawfish typically avoid pure freshwater, but may occasionally move far up rivers, especially during periods when there is an increased salinity. There are reports of narrow sawfish seen far upriver, but these need confirmation and may involve misidentifications of other species of sawfish.
Smooth toadfish
The smooth toadfish is found along Australia's eastern and southeast coast, from Moreton Bay in southeastern Queensland to Port Lincoln in South Australia as well as Kangaroo Island and Tasmania. It is one of the most abundant fishes in the muddy areas of Port Philip Bay. It generally lives in shallow water less than 3 m (10 ft) deep, often over mudflats in estuaries. In areas of seagrass beds, smooth toadfish are more commonly found in sand areas bordering on the seagrass patches. They are more commonly found in seagrass patches in water less than 1.5 m (5 ft) deep rather than deeper water of 3.5–6 m (11–20 ft). A South Australian field study on wrack and associated fauna found that the smooth toadfish was associated with larger volumes and aggregations containing green algae.