Underwater Halloween Costume Ideas

Halloween only rolls around once a year, which means you'll need to dedicate some time to producing only the most interesting or shocking costume possible. Taking some ideas from the Amazon River to the deep blue sea is always a great way to gain inspiration.


A classic costume that often goes overlooked is the mighty shark. Whether the costume is for a little kid or an adult, most people will smile when they see someone show up in a shark costume on Halloween night.

• The Fin

The most important feature of a shark costume is its fin. In fact, for a really quick shark costume, all you'll need to create is a fin. You can do this by using foam rubber, a couple of cloth belts, gray spray paint, and a little bit of sewing. Simply cut a fin shape out of the foam rubber. Put the two cloth belts on the costume wearer.

The top one should be placed at the widest part of their chest. For women, this means just below the breasts Attach the second one across the top part of the stomach. Use safety pins to place the fin on the back of the straps. Remove the costume, sew the fin in place, and remove the safety pins. Spray paint the entire apparatus gray and your shark fin is ready to go. This costume works even better when paired with gray clothing such as a gray long-sleeved shirt and gray sweatpants.

For a slightly more detailed shark costume, you'll need a hot glue gun, a gray sweatshirt, and a few pieces of very stiff felt. Specifically, you'll need a few sheets of white felt, one sheet of black felt, and two fairly large sheets of gray felt.

• The Head

The hood of your gray hoodie is going to be your shark's head. On either side of it, glue two small circles of black felt for the shark's eyes. Next, cut out triangles of white felt, these will be your shark's teeth. The teeth will be glued all along the inner edge of the hood so that they stick out like teeth.

Now that we have the shark's head perfected, it needs a fin. Using the gray felt, cut out two identical pieces of fin-shaped material. Glue them together, leaving a few unglued inches at the bottom of the fin (where it will attach to the hoodie).

These two bits of unglued fin material will be spread to either side so that when you glue the fin to the back of the hoodie, it will be held relatively upright. Complete this final task and your gray hoodie has been turned into a frightening (well maybe not so frightening) shark. Have fun!


Halloween only rolls around once a year, which means you'll need to dedicate some time to producing only the most shocking costume possible. Taking some ideas from the deep, dark blue sea is always a great way to gain inspiration.

• The Body

Jellyfish are famous for their round, squishy bodies, which is why you can't nail the look without getting this step right. Luckily, it's easier than you might think, as you can purchase a clear blue bubble umbrella from practically any local retailer.

Now, you could keep the umbrella as it is and call it a day, but where's the fun in that? To spark things up a bit, use tape or Velcro to line the interior with purple fairy lights and make your jellyfish costume light up the night!

• Eyes And Tentacles

If your jellyfish needs a little personality, slap on a pair of eyes to the front of the umbrella using sturdy cardboard paper and glue.

Finally, the costume isn't complete without a proper set of tentacles. You can make these with anything from an old sheet to fancy gift-wrapping ribbon, but you'll need to make sure they're glued and taped securely to the inside of the umbrella. Now swim on over to your next Halloween party, and get ready to shock everyone with your creativity!

Killer Piranha

When someone says the word "piranha" the most common image conjured in the mind is that of the rabid, killer fish with razor-sharp teeth and an insatiable appetite for blood and flesh. What better idea for a costume than the vicious piranha.

• Costume Basics

With the success of popular horror films like Piranha (1978) and its 2010 remake Piranha 3D, the freshwater fish has never had a more sinister reputation.

To start display as much of your skin as possible, so try your best to wear short shorts and either no shirt or a skintight Under Armor shirt. Remember, piranhas have an orange and silver skin tone, so body paint is going to be a major aspect of this costume. Using orange body paint, apply it to your kneecaps, rib area, abdomen, forearms, and shoulders.

• Body

Apply silver body paint generously to the other exposed areas of your body. Use glitter and sprinkle it across your body while your skin is still wet from the paint - this will create a glistening scale effect. Using foundation makeup, apply some to various parts of your body and press a fishnet cloth over it to create lines that mimic scales. Sprinkle glitter on this part as well.

Using silicon makeup, apply prosthetic to the ends of your elbows and along your back to create fins, although this 3D component is not vital in the overall grand scheme of things. Although piranhas are typically orange and silver, some may even appear to have other colors too, such as green, grey, and light blue. Of course, there are no rules when creating a terrifying costume, so do not be afraid to use some unique color patterns.

• Face

A major part of this costume is making a face scary enough to make a true piranha proud. Remember, this isn't a beauty contest, it's a spooky one! Using some black eyeliner, create 3 curved lines on your cheek, making gills to breathe from. Insert green or red contacts to instill fear in the hearts of those with whom you come in contact. Next, buy fake fangs/teeth from either Amazon or your local craft store.

• Teeth

The gnarly teeth are perhaps the most important part of the costume, as this is the body part that does the most devastating damage. Be sure to flaunt these teeth and drizzle some fake red blood on the ends of the teeth to let people know you are not afraid to attack. Given that piranhas are prone to even fighting with one another, do not be afraid to institute some "battle damage" effects, such as fake wounds and blood.

Given that transforming a human into a fish is a seemingly difficult task, if you show up to a Halloween party as a human-fish hybrid, you'll definitely earn the respect (and fear) of those attending!


With Halloween rolling around, you might be scrambling to discover the best costume to impress your friends or surprise your kids with. All you need is some ingenuity to make a costume that'll blow everyone else out of the water (pun intended).

• The Body

You can't plunge into the water without the right equipment, which is why you'll need to start your process by searching for a suitable body. In this case, an oversized orange sweatshirt or onesie can work as a goldfish outer shell. If you don't have anything with a hood, an orange trapper hat can suffice. Of course, orange sweats or shorts are also a must.

• The Scales

For this step, all you'll need is a good supply of red, orange and yellow cloth that you can cut into circles (glitter is a plus). Once you have a dozen or so ready to be attached, glue them across the body in a scale-like pattern, and watch them shimmer like the real thing!

• Eyes & Fin

Practically any Styrofoam ball you find at a local craft store can become a set of goldfish eyes with some scissors and glue - just don't forget to color in the pupils.

Finally, a sheer, golden piece of fabric attached to the back of your costume can work as your majestic set of fins. Now get ready for a long night of trick-or-treating, watch out for sharks, and enjoy being the coolest fish in the sea!

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