Basics of Fly Fishing: Trout Food Series - Top Tips on the Types of
Mayfly Nymphs

1. The Different Types of Mayfly Nymphs:
There are four basic types of mayfly nymphs - the burrowers, swimmers,
clingers and crawlers
. Each of these types of nymphs have their own particular
habitat and behavior. When you imitate any mayfly nymph, you should first
determine which type of nymph it is, otherwise you wouldn't know where and how to
fish the fly imitating the nymph. Our next several tips will provide the keys things you
need to know about the different types.
There are 29 categories of mayflies that represent all the major mayfly species in
trout waters in the U. S. and Canada
included on this list. Beside each one is the
type of nymph the particular mayfly is - clinger, swimmer, crawler or burrower.
worry about all the other detail now
. Just remember this chart will tell you what
type of nymph any mayfly is.

2. Swimmer Mayfly Nymph Habitat:
Swimmer nymphs are all slim, streamlined minnow-like nymphs.  They are basically
round in shape and have tails shaped to help propel them. They hide wherever
they can find cover. Rocks, pebbles and grass are key things they hide in and
around. They avoid fast water but are found in areas of slow to moderate water that
borders fast water. You can imitate them anytime. There are quite a few swimmers
in the Smokies.

3. Swimmer Mayfly Nymph Behavior:
These nymphs act more like minnows than nymphs. They move around with quick,
darting motions. When you imitate them with a fly, you may want to add a small
amount of darting action to the fly.

4. Burrower Mayfly Nymphs Habitat:
Burrower mayfly nymphs spend most all of their life in holes or burrowers in the
banks or bottom of streams and lakes. They only come out to feed, usually at night,
and to molt into larger nymphs. This happens only a few times during their life and
only for a short time. Imitating them on a normal day to day basis, is mostly a waste
of time. They should be imitated with a fly when they move out of their burrows to
hatch. They are exposed and available for the trout to eat during that time. There
are very few burrowers in the Smokies.

5. Burrower Mayfly Nymph Behavior:
The typical burrower nymph is a clumsy, poor swimmer. It wobbles its tail and body
in such a manner that its movements can propel it from the bottom to the surface to
hatch but that is the full extent of its swimming behavior. You want to add action to
the fly you use to imitate these nymphs hatching similar to the wobbling motion of
their body and tail.

6. Clinger Mayfly Nymph Habitat:
Clinger mayfly nymphs live underneath rocks and pebbles on the bottom of the
stream. They are almost always located in moderate to fast moving water. They
require a lot of oxygen. You will find them under rocks in the riffles and runs of a
stream. They only come out of their hiding places to feed, usually in low light
conditions or at night. When they get ready to hatch, they move from their fast
water habitat to slower moving water that is close by such as pockets and the edges
of fast water near banks. Imitating them with a fly is only highly effective prior to the
hatch. Imitating them any other time has low odds of success. Clingers represent
the majority of mayfly nymphs found in the Smokies.

7. Clinger Mayfly Nymph Behavior:
Clinger nymphs crawl on the bottom from their fast water habitat to slower water
prior to the hatch. This can be anywhere from a few days to several hours before
they hatch. Some hatch on the bottom, a very few mid depths and most of them on
the surface depending on the particular species. They swim to the surface slowly in
a crude fashion using their tails and gills.

8. Crawler Mayfly Nymph Habitat:
Crawler mayfly nymphs get down between rocks and pebbles but not underneath
them. Some species hide in grass. They are available for the trout to eat anytime
the trout can find them. They are very much available and exposed to the trout prior
to their hatch. They are found in moderately fast water to slow water, so their
habitat is of little help in knowing where they exist or where to fish because it covers
such a wide range of water types..Crawlers are not very common in the Smokies but
are found in good concentrations in a few isolated areas.

9. Crawler Mayfly Nymph Behavior:
Crawler mayfly nymphs do as their name implies and crawl along the bottom when
they come out from their hiding place. They usually do this to feed. They are very
much exposed to hungry trout during this time. They are also available when they
are hiding, it is just not as easy for the trout to find them. When you are imitating
them you want to keep your fly right on the bottom. You do not need to imply any
action to the fly.

Copyright 2009 James Marsh