It can be hard to find practical fish costume for children online or in a costume shop; most are either just a big fish hat or are large and uncomfortable. These can also be expensive. To make an easy fish costume for your child all you really need is an orange sweat suit, a piece of felt and little artistic talent.
To make the back fin, measure child with hooded shirt on, from the top of the head to back hem of shirt. Cut a strip of felt this long and about 5 inches wide. Cut it straight on one side and in a waving line on the other. Sew the fin with waving edge sticking straight up, to the sweat shirt from top of the head to the hem of the shirt.
To make the side fins measure child from under the arm to the wrist. Cut a piece of felt 10 inches wide and this length. Cut in half diagonally. You will have two triangles. Sew the side of the triangle that is length of the child's arm to the underside of the shirt sleeve with the base of the triangle at the wrist. Cut the other sides of triangle into wavy lines. Do the same with other triangle on other sleeve.
To make the tail fin, measure child from knee to ankle. Cut a piece of felt 10 inches wide and this length. Cut in half diagonally. You will have two triangles. Sew the side of the triangle that is length of the child's shin to the outside of sweat pants with the base of the triangle at the ankle. Cut the other sides of triangle into a wavy line. Do the same with other triangle on other leg.
To make the eyes, cut the plastic foal ball in half. Glue a goggle eye to centre of round side of each half. Glue balls, flat side down, to top front of hood, very near the opening.
Use fabric paint and a picture of a goldfish (to copy) to paint scales and texture on your costume.
Have your child wear the hood with the drawstring tight so that the eyes and top of back fin can be seen from the front.