When is the Freshwater Shrimp most available to trout?

January–December, typically All day. It picks up from about 4°C, peaks around 12°C and tails off by 22°C.

What flies imitate the Freshwater Shrimp?

Czech Nymph, Killer Bug, Gold Ribbed Hare's Ear, Pink Shrimp, typically on a #10–8 hook.

How big is the Freshwater Shrimp?

Adult stage: 14–21mm. That matches a #10–8 hook.

Crustacean · Aquatic invertebrate

Freshwater Shrimp

Gammarus pulex

Size

14–21mm

Hook size

#10–8

Always there

No hatch and no season — this is in the water every month of the year, so it's always a fair bet when nothing is showing on top.

How fish feed on it

No hatch to wait for and no season to miss — shrimp and hoglice are in the weed and the gravel every day of the year, and trout eat them steadily whether anything is happening on the surface or not. Fish them slow and close to the bottom. On a cold day when nothing is moving, this is very often what the fish are actually doing.

Flies that imitate this

Czech Nymph

Killer Bug

Gold Ribbed Hare's Ear

Pink Shrimp

Ecology

Rivers & stillwaterTailwatersChalk streamsTolerates poor water

Where you'll find this

British IslesPresent
IberiaPresent
The AlpsPresent
ScandinaviaPresent
Continental EuropePresent
Atlantic fringePresent
North America — WestPresent
North America — EastPresent
East AsiaPresent
New ZealandPresent
PatagoniaPresent

Present throughout

Identification

Gammarus pulex is a species of amphipod crustacean found in fresh water across much of Europe. It is a greyish animal, growing to 21 mm (0.83 in) long.