Rainbow Fish Costume for Book Week

Looking for a beautiful Rainbow Fish costume for Book Week? This easy outfit uses a shimmering scale dress, sparkly cape and colourful accessories to recreate the magical look of Marcus Pfister’s much-loved picture book character.

Some Book Week costumes are all about cardboard, cutting and sticking. Others come together mostly through the outfit itself, and this Rainbow Fish costume definitely falls into that category.

With its iridescent scales, flowing cape and soft pastel colours, it instantly captures the feel of The Rainbow Fish. Add the book in hand and the whole look becomes immediately recognisable.

It is also a lovely option for children who want something bright, pretty and comfortable enough to wear for the school day.

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What You Need for a Rainbow Fish Book Week Costume

To recreate this look, you’ll need:

Start With the Rainbow Fish Dress

The dress is what makes this costume work straight away.

A shimmery scale-print dress is perfect because it already captures the fish-like look without needing much extra crafting.

The pastel blues, pinks and purples work beautifully for the magical underwater feel of The Rainbow Fish.

Because the dress already has so much colour and detail, you don’t need to overcomplicate the rest of the costume.

Add a Sparkly Cape for the Fins and Tail Effect

The cape is such a clever finishing touch for this costume.

Rather than trying to build a full fish tail or fins from scratch, a sparkly cape adds soft movement and shimmer, helping create that flowing underwater look.

It also gives the costume more impact from the back, particularly as your child walks through the Book Week parade.

If you don’t want to use a ready-made cape, you could create something similar using:

Tulle
Organza
Ribbon
Iridescent cellophane
Fabric scraps in blue, purple, aqua and pink

But using a ready-made sparkly cape is definitely the quickest option.

Add Purple Braided Hair

The purple braided hair extensions are a really fun addition and make the whole costume feel a little more special.

Braiding coloured extensions into the hair ties in beautifully with the pastel and shimmery colours of the dress and cape.

This step certainly isn’t essential, but it adds another splash of colour and helps the costume stand out.

You could also use:

Coloured ribbon braided through the hair
Clip-in hair extensions
Temporary hair chalk
Wash-out coloured hair spray

Add Fish Earrings and Face Gems

The little accessories are what really pull the Rainbow Fish look together.

For our costume, we added fish-themed earrings and colourful face gems.

The gems work particularly well because they echo the shiny scales from the story. You only need a few around the eyes or cheek area to add a lovely shimmering effect.

If your child doesn’t have pierced ears or doesn’t like wearing earrings, simply leave them out.

You could swap them for:

A shell bracelet
Glittery hair clips
An ocean-themed necklace
More colourful hair accessories

Finish the Look With Sparkly Shoes

We finished the costume with white socks and sparkly shoes.

You definitely don’t need to buy special shoes for this costume. Ballet flats, glittery party shoes or anything silver, pink or pastel will work beautifully.

More importantly, choose something comfortable enough for your child to wear throughout the school day.

Don’t Forget The Rainbow Fish Book

One of the easiest ways to make any Book Week costume instantly recognisable is to simply carry the book.

In this case, carrying a copy of The Rainbow Fish makes the costume completely clear and adds a lovely finishing touch for photos.

It also saves you from feeling like every tiny element of the costume needs to perfectly match the character.

The outfit captures the colours and shimmering scales, while the book tells everyone exactly who your child has come dressed as.

Why This Rainbow Fish Book Week Costume Works So Well

This costume is a lovely Book Week option because it feels special without requiring hours of complicated DIY work.

It works because:

The dress already provides the colourful fish-scale look
The cape adds movement and plenty of shimmer
The colours are bright and eye-catching
The accessories add extra personality
It is comfortable enough to wear during the school day
The book makes the character immediately recognisable

It is also a great alternative if your child loves dressing up but isn’t keen on a costume made from cardboard, masks or bulky props.

How to Make a Last-Minute Rainbow Fish Costume

If you don’t have time to recreate every element, you can easily simplify the costume.

Start with whatever colourful or sparkly clothes you already own.

A simple last-minute version could include:

Blue, aqua, purple or rainbow dress
Sparkly or colourful cape
Face gems
Colourful hair ribbons
Glittery shoes
A copy of The Rainbow Fish

You could also cut a handful of scale shapes from metallic wrapping paper or aluminium foil and attach them to an existing blue dress or top.

The most important elements are the rainbow colours, shimmering scales and the book itself.

More Easy Book Week Costume Ideas

Looking for more Book Week inspiration? Take a look at some of our other easy DIY costume ideas:

A Rainbow Fish costume is such a gorgeous choice for Book Week. With a shimmering scale dress, flowing cape and a few sparkly accessories, it is easy to create a look that feels magical, recognisable and perfect for parade day.