The Coliban is an intimate little river. It leaves forest for open farmland on its way to Upper Coliban Reservoir, so the character of the river changes along its length. Below Trentham Falls it is more like a small flowing creek, and further down toward the reservoir it becomes slower and flatter.

The bed is a mix of bedrock, gravel, strap weed and fallen timber. That gives trout plenty of places to sit, and it gives you snags to respect.

It can be quite overgrown, which is why anglers often skip short sections to find more open, accessible water. Expect to walk past some of it.

Platypus and rakali live here too, so a quiet approach pays twice.

Brown trout are the fish to plan for. FlyLife describes a small wild population, and small trout eating big dry flies from late spring into summer is one of the river’s listed highlights.

The river also supports small native fish such as flat-headed gudgeon and mountain galaxias. They are not the fish you came for.

For flies, the listed patterns are a Chubby Chernobyl Ant in sizes 10 to 12 and a grasshopper in sizes 10 to 14. Both suit trout that are willing to eat something big off the top.

FlyLife lists late spring into summer as the time for small Coliban trout eating big dries, provided the water is not too low. One angler has also had trout eat a Chernobyl Ant and a grasshopper in September, so a big dry is a fair thing to try then.

Flows matter on this river. The Victorian Environmental Water Holder notes that summer and autumn flows below Malmsbury Reservoir can become critically low and low in oxygen, so a hot spell after a dry stretch is a reason to fish somewhere else or to fish early and gently.

Because of its size, depth and pace, the Coliban lends itself to dry-fly fishing. Fish a Chernobyl Ant or a hopper and expect a willing take: Coliban trout will eat a big dry aggressively, so long as the water is not too low.

In higher flows or deeper holes, put a nymph under the dry.

The Springhill Road bridge is a practical public entry. It describes where you can get to the water; it is not a statement of permission, so read any sign or fence you meet.

As on any bush river, tell someone where you are going and when you will be back, watch your footing on wet bedrock and around fallen timber, and turn back if the water rises.

Before you fish, read the current Victorian Fisheries Authority inland angling guide, including its closed-waters list, and take any season, bag and size limits and licence requirements from it.