How to catch trout during a Caenis hatch

Caenis are our smallest upwinged mayfly and aren't known as the Angler's Curse for nothing. They're tricky to tie, tricky to tie on, tricky to see on the water and tricky to catch fish with...

Picture copyright © Davie McPhail
Fly fishing tips Estimated reading time 3 - 4 minutes

What are Caenis?

Caenis are one of the smallest species of so called "upwinged" flies and are related to the larger mayfly species also common in the summer months. They typically hatch in the afternoon or evening on still summer days.

Caenis though are much, much smaller, and when the trout feed upon them they become extremely selective, ignoring everything else they're offered.

This has earned them the name of Angler's Curse. If you've tried to catch trout on anything during a Caenis hatch you'll soon realise why that name is so apt.

Why is it so hard to catch trout feeding upon Caenis?

The main reason why Caenis make things difficult for the fly fisher is their small size. They're ruddy small, maybe size 20 at the most and down to size 28 at times.

The second is the sheer number of them that can hatch at once. They become very abundant during hatches and literally thousands can cover the water. When that happens the trout will sip at them extremely confidently, ignoring pretty much anything you care to throw at them.

With so many naturals covering the surface, it's pot luck as to whether the trout find your fly among the dozens of real ones sitting upon the surface film, which greatly reduces your chances of hooking up.

Are they always most common in the evening?

No, it depends on the species. There are at least eight Caenis species found in the UK (Caenis beskidensis, C. horaria, C. luctuosa, C. macrura, C. robusta, C. pusilla, C. pseudorivulorum and C. rivulorum) and some are most common in the morning, rather than in the evening.

How do you fish a fly so small?

If you've got dodgy, ageing eyes, just tying a Caenis fly pattern on your hook can be a challenge in itself. Many are now tied on hooks that have slightly oversized eyes, which does make that a little bit easier, but you'll still need a fine tippet.

Getting the trout to spot your fly won't be easy if there are thousands covering the water. Casting at feeding fish and landing your fly near their nose could be the best tactic to adopt, as the chances of them mopping up yours when it's fished static aren't high.

The next challenge will be landing the trout. As they're so tiny, the hooks can straighten on larger fish. However, better hook designs and wider gapes mean that's less of a problem than it used to be.

You might need to use lighter tippet than you should really be using, so a soft actioned rod to cushion the light tippet will be helpful.

What sort of fly patterns are best for a Caenis hatch?

Personally, I find these tiny little flies incredibly tricky to tie, so I tend to buy mine. There are some beautifully delicate hackled patterns with micro fibbet tails that look very impressive, but they're too fiddly for me.

The one pattern I can just about manage to tie is Davie McPhail's simple CDC Caenis. Davie uses a Kamasan B160 hook in a size 16, which has a shank equivalent to an 18 and a wider gape, so it can handle reasonably sized trout and is a bit easier to tie.

It's a simple fly, consisting of a white CDC wrapped body, half a dozen cock fibres for a tail, and a couple of tiny CDC puffs for wings.

It works really well, and is easy enough to spot on the surface, but if you don't have one in your fly box, a tiny F-fly will do almost as well. 

About the author



No comments yet. Go on, be the first to comment...

Fly fishing diary: July 2022 George's team wins silver at the International Youth Fly Fishing Championships on Lough...

Fly fishing diary: June 2022 We fish the mountain lakes of Snowdonia including Llyn Bugeilyn, Llyn Gamallt Fawr, and...

Fly fishing diary: May 2022 We have two cracking days on the boat at Llyn Brenig and Blithfield Reservoir and some...

How to get into youth competition fly fishing Everything you need to know to get started in competitive youth fly fishing so you can...

We're running FREE junior fly fishing coaching courses George and I are running FREE junior fly fishing coaching sessions for members of...

Fly fishing diary: January 2022 We have a few sessions Euro nymphing on the Welsh Dee and George catches a new personal...

Fly fishing diary: December 2021 We fished at Llandegla Fishery and Ellerdine Lakes, where George won the annual Fur and...

Fly fishing diary: November 2021 We fish at Ellerdine Lakes, Llyn Brenig, and Llandegla and enjoy some superb winter...

Fly fishing diary: October 2021 After being struck down with COVID 19, we get back out on the bank and enjoy some...

Get fly fishing updates

You may unsubscribe at any time. Check our privacy policy for details on how we use and protect your data.