Crochet Koi Fish Pattern: Butterfly Wave Amigurumi Plushie — Complete Ocean Animal Tutorial (PDF Download)

There is something quietly magical about crocheting a koi fish. The graceful sweep of their fins, the gentle curve of their bodies, the way they seem to float even when sitting still on a shelf — everything about them translates beautifully into amigurumi. This Butterfly Wave Koi Fish pattern is one of my absolute favorites to make and to share, and today I am walking you through every single stitch, tip, and finishing trick so that you can create your own stunning plushie from start to finish.

Whether you are a seasoned amigurumi maker or someone who has just learned the magic ring, this pattern is written with you in mind. I have included detailed instructions, stitch counts in brackets, notes on yarn and hook selection, and photos at every major turning point. A full PDF download is also available at the end of this post so you can print it out, take it to your favorite chair, and crochet without staring at a screen.

Let’s dive in.

Why Koi Fish Make the Perfect Amigurumi Project

Koi are one of those subjects that look incredibly complex but are surprisingly approachable once you break them down into individual components. The body is worked in the round using basic increases and decreases. The fins are flat pieces that get attached with just a few whipstitches. The tail, which gives this particular pattern its “Butterfly Wave” name, is the showstopper — a dramatic double-lobed shape that fans out behind the body like a gown trailing across the floor.

These plushies make extraordinary gifts. They are popular for nurseries, desks, meditation spaces, and zen-themed home décor. They photograph beautifully for craft fairs and Etsy shops, and because koi come in so many real-world color combinations — red and white, black and gold, calico, tangerine, and platinum — you can make an entirely different-looking fish every single time using the same exact pattern.

This is also a pattern with wonderful opportunities for customization. Want a more dramatic butterfly tail? Add extra rows. Want a rounder, chubbier koi? Reduce your decreases by a row or two. Want sparkle? Sub in a held strand of fine metallic thread alongside your main color. This tutorial is a starting point, not a ceiling.

Materials and Tools

Before you cast on your first stitch, gather everything you need. There is nothing more frustrating than reaching a critical step and realizing you are out of stuffing or cannot find the right color for the fins.

Yarn: You will need a soft worsted weight yarn (weight 4) for the body. Choose two or three coordinating colors for a traditional koi look. A classic combination is white as the base, coral or orange for the markings, and black for any spot detail. You can also work in a single gradient color for an elegant single-tone fish. For the fins and tail, a slightly lighter, more translucent yarn in a coordinating shade adds a beautiful layered look, but the same yarn works perfectly well too.

Hook: A 3.5mm or 3.75mm crochet hook works well with worsted weight yarn for amigurumi. You want a slightly tighter tension than you would use for a blanket or garment so that the stuffing does not show through the fabric. If your gauge is naturally loose, drop down to a 3.25mm hook.

Stuffing: Premium polyester fiberfill. Use enough to give the body a firm, rounded shape without stretching the stitches. For amigurumi, a firmer fill generally looks better and holds the fish’s shape over time.

Safety eyes: Two 9mm or 12mm black safety eyes. If you are making this for a child under three, skip the safety eyes and embroider the eyes with black yarn instead.

Notions: A yarn needle, stitch markers, small scissors, and pins for positioning fins and tail before sewing.

Pattern Notes and Abbreviations

This pattern is written in US crochet terms.

MR — Magic ring
ch — Chain
sl st — Slip stitch
sc — Single crochet
inc — Increase (2 sc in the same stitch)
dec — Invisible decrease (insert hook through the front loop only of the next two stitches, yarn over, pull through both loops, yarn over, pull through remaining two loops)
BLO — Back loop only
FLO — Front loop only
[ ] — Stitch count at end of round
( ) x — Repeat instructions in parentheses the indicated number of times

Work in continuous rounds unless otherwise noted. Use a stitch marker to mark the first stitch of each round.

The Koi Fish Body

Round 1: In MC (main color), MR, 6 sc into ring. Pull ring closed. [6]

Round 2: Inc in each st around. [12]

Round 3: (Sc 1, inc) x 6. [18]

Round 4: (Sc 2, inc) x 6. [24]

Round 5: (Sc 3, inc) x 6. [30]

Round 6: (Sc 4, inc) x 6. [36]

Round 7: (Sc 5, inc) x 6. [42]

Rounds 8–10: Sc in each st around. [42]

This is a good point to add your safety eyes if you are using them. Position them between rounds 5 and 6, about 8 to 10 stitches apart. Secure the washers firmly on the inside.

Round 11: (Sc 6, inc) x 6. [48]

Rounds 12–16: Sc in each st around. [48]

At this point you can switch to your color change yarn if you are doing markings. You do not need to cut the main color — simply carry it loosely along the inside or twist the yarns at each color change to avoid holes. For a simple two-color koi, work a section of approximately 12 stitches in your contrast color (CC) for rounds 12 through 16. This creates the characteristic saddle marking across the back.

Round 17: (Sc 6, dec) x 6. [42]

Rounds 18–20: Sc in each st around. [42]

Round 21: (Sc 5, dec) x 6. [36]

Round 22: Sc in each st around. [36]

Round 23: (Sc 4, dec) x 6. [30]

Begin stuffing the body firmly at this point if you have not already. Continue stuffing as you go.

Round 24: Sc in each st around. [30]

Round 25: (Sc 3, dec) x 6. [24]

Round 26: Sc in each st around. [24]

Round 27: (Sc 2, dec) x 6. [18]

Round 28: (Sc 1, dec) x 6. [12]

Round 29: Dec x 6. [6]

Add any final stuffing to make sure the tail end is firm. Fasten off and close the opening by weaving the yarn tail through the front loops of the remaining six stitches, pulling tight. Weave in the end securely inside the body.

The Pectoral Fins (Make 2)

These are the side fins — two small, paddle-shaped pieces that attach just behind and below the eyes, giving the koi that lovely gliding silhouette.

Row 1: In CC or fin color, ch 8, turn.
Row 2: Starting in second ch from hook, sc 7, ch 1, turn. [7] Row 3: Dec, sc 3, dec, ch 1, turn. [5] Row 4: Dec, sc 1, dec, ch 1, turn. [3] Row 5: Sc 3, ch 1, turn. [3] Row 6: Dec, sc 1. [2]

Fasten off, leaving a long tail for sewing. Fold the fin gently in half lengthwise and pin it against the body, curving it slightly outward. Use your yarn needle to whipstitch it in place. Position one fin on each side of the body, roughly at the widest point, angling slightly downward.

The Dorsal Fin

The dorsal fin runs along the top of the koi from roughly the midpoint to just before the tail. It is one of the most distinctive features and gives your amigurumi that immediately recognizable koi silhouette.

Row 1: In MC or a blend of MC and CC for a variegated look, ch 14, turn.
Row 2: Starting in second ch from hook, sc 13, ch 1, turn. [13] Row 3: Sc 13, ch 1, turn. [13] Row 4: Dec, sc 9, dec, ch 1, turn. [11] Row 5: Dec, sc 7, dec, ch 1, turn. [9] Row 6: Dec, sc 5, dec, ch 1, turn. [7] Row 7: Sc 7, ch 1, turn. [7] Row 8: Dec, sc 3, dec. [5]

Fasten off with a long tail. Do not stuff. Pin it along the spine of the body with the widest edge aligned with the midpoint and the narrow end pointing toward the tail. Whipstitch it along the base, being careful to keep the fin upright and centered.

The Butterfly Wave Tail

This is the heart of the pattern. The Butterfly Wave tail is a dramatic double-lobed piece that fans out behind the body like a flowing gown. It is worked in two mirrored halves and then joined at the center, creating that characteristic butterfly wing shape.

Upper Tail Lobe (Make 1):

Row 1: Ch 16, turn.
Row 2: Starting in second ch from hook, sc 15, ch 1, turn. [15] Row 3: Inc, sc 13, inc, ch 1, turn. [17] Row 4: Inc, sc 15, inc, ch 1, turn. [19] Row 5: Inc, sc 17, inc, ch 1, turn. [21] Row 6: Sc 21, ch 1, turn. [21] Row 7: Sc 21, ch 1, turn. [21] Row 8: Dec, sc 17, dec, ch 1, turn. [19] Row 9: Dec, sc 15, dec, ch 1, turn. [17] Row 10: Dec, sc 13, dec, ch 1, turn. [15] Row 11: Dec, sc 11, dec. [13]

Do not fasten off yet. Work a single crochet border all the way around the outer curved edge of the lobe to give it a clean, polished finish. Fasten off with a long tail.

Lower Tail Lobe (Make 1):

Work exactly as the upper tail lobe. Fasten off with a long tail.

Joining the Tail:

Hold both lobes together so they mirror each other with their straight edges meeting. Using a strand of MC yarn and a yarn needle, whipstitch them together along the straight joining edge. This creates the center seam of the butterfly tail. Press the tail lightly flat — you can use a damp cloth and a warm iron on a low setting if your yarn is appropriate for heat, or simply use your fingers to smooth it into shape.

Pin the assembled tail to the back end of the koi body, centered and straight. Whipstitch firmly around the full attachment edge. Take your time here — the tail is the focal point of the whole piece, and a secure, even attachment makes an enormous difference.

Adding Color and Surface Details

Now comes the fun part: bringing your koi to life with color and texture.

If you did not work color changes into the body itself, you can use duplicate stitch embroidery or surface slip stitch to add markings after the fact. Thread a length of CC yarn onto your yarn needle and work long, sweeping stitches across the body in the pattern of your choosing. Traditional koi markings are bold, asymmetrical patches — not careful, symmetric spots. Embrace irregularity here. The less deliberate they look, the more authentic.

For black spot details, you can use a tiny bit of black yarn embroidered on with just two or three stitches. Position spots near the top of the body or at the base of the dorsal fin.

To highlight the fins and tail and give them that delicate, translucent look, take a strand of white or cream yarn and work a loose running stitch along each fin from base to tip. This suggests the fin rays you see in real koi and adds wonderful texture.

Finishing Touches

Once all pieces are attached and your fish looks the way you want it to, weave in any remaining ends. Thread each yarn tail into the interior of the body so that it disappears completely. Take a moment to look at your fish from every angle and adjust any fins or tail pieces that have shifted.

If you want, you can add a few details with dimensional fabric paint — a small dot of white on each eye for highlight, a thin orange or red line along the mouth. These take only seconds but give the face enormous personality.

A light misting of water and a gentle reshaping while the piece is damp can help any parts that have curled to lie flat.

Customization Ideas for Your Butterfly Wave Koi

One of the greatest pleasures of this pattern is how endlessly flexible it is. Here are some variations to inspire your next fish.

A metallic koi using a silver or gold metallic yarn held together with a white sport weight yarn creates a shimmering, ethereal effect that catches the light beautifully and photographs like a dream for Etsy listings.

A tancho koi — one of the most iconic koi varieties — is worked entirely in white with just a single circle of red embroidered on the top of the head. Simple, striking, and dramatic.

A butterfly koi with longer fins is achieved by simply adding more rows to each fin before beginning the decreases. Doubling the fin rows creates a lush, flowing effect that earns oohs and aahs at every craft fair.

For a mobile or garland, make five or six koi in different colors, attach each to a length of invisible thread, and hang them from a painted wooden dowel. This makes one of the most gorgeous nursery mobiles I have ever seen.

Tips for a Professional-Looking Finish

Tension is everything in amigurumi. If your stitches are too loose, the stuffing will show through and the fabric will look uneven. If they are too tight, you will struggle to insert your hook and your hands will tire quickly. Aim for a fabric that is firm but not strained.

Invisible decreases make a significant difference in the look of a finished amigurumi. The standard single crochet decrease creates a visible ridge that can interrupt smooth color work. The invisible decrease, worked through the front loops only, lies flat and nearly disappears.

When sewing on fins and the tail, use the same yarn as the piece you are attaching rather than a separate sewing thread. This ensures the seam blends naturally and will not wear differently over time.

Stuff gradually. It is far easier to add stuffing as you close up the body than to try to force more in at the very end. A chopstick or the blunt end of a pencil is useful for pushing stuffing into small curved areas without distorting the fabric.

PDF Download

The full Butterfly Wave Koi Fish Amigurumi PDF includes every round written out clearly, a materials list, abbreviation guide, step-by-step photos of the fin and tail construction, and a finished size guide. It is formatted for easy printing on standard letter or A4 paper. You can find the download link in the resources section below or at the top of this page.

The PDF is designed to be printer-friendly — clean white background, clear fonts, and photos sized to print legibly without requiring a color printer.

A Note on Sharing Your Work

If you make this pattern, I would absolutely love to see your finished koi. Tag your project on Instagram or Ravelry so the whole community can admire your work. Seeing all the different color combinations and customizations that makers bring to this pattern is one of my greatest joys, and your version is guaranteed to be uniquely beautiful.

Koi are symbols of perseverance, transformation, and good fortune in many cultures. There is something lovely about the fact that making one requires patience and care — the very qualities the fish itself is meant to represent. Whether you are making this for yourself, as a gift, or for your shop, I hope