Of all the odors that can stink up your clothing, a fishy smell is one of the worst. It seems to lurk just below the surface so that you don't notice it right away. But when it's there, it's there, and detergent fragrances never quite seem to cover it up. Therefore, the solution is to get it completely out of the fabric. There are several simple home remedies that are easy and cheap, but be aware that a serious odor problem can take a little time and might require repeated treatments.
Try any or all of the following to rid your clothes of that fishy smell once and for all.
Baking Soda Soak
Baking soda can be a great tool to remove laundry odors. It can get out not just fish odors, but also smoke, sweat, and mechanical smells from laundry. You may have used it before, but have you ever tried presoaking the clothes? Mix 1/2 cup of baking soda in a bucket of water or a sink full of water, add or 1 cup of baking soda in a washing machine filled with warm water, and allow your laundry to soak in it for as long as overnight. Then, launder as usual at the highest water temperature recommended for the garment.
Baking Soda Sprinkle
If you won't be laundering your clothes right away, you can let the waiting time work for you. Place the clothes in a paper bag and sprinkle them liberally with baking soda. Set the bag aside until you have a full load to wash or you want to soak several items with baking soda and water (as discussed above).
The baking soda will be absorbing odors the whole time they're in the paper bag.
Wash as Warm as Possible
Hot water—or at least very warm water—can make a big difference when removing a fishy smell. Wash your clothing in the hottest water temperature recommended for the fabric. Be sure to check the care label to confirm that the fabric can take it.
To minimize shrinkage after a hot or warm wash, give the fabric a gentle tug while it's still wet (to stretch the fibers a bit), then line-dry the garments rather than machine drying. Be aware that some fabrics shrink in hot or warm water, whether they're line-dried or not.
If the clothing still smells fishy, you may have to try a more intense soaking. Fill a large bucket with very warm water. Add baking soda, laundry detergent, or a commercial laundry odor-eliminator product. Place the clothing in the bucket and cover it with a clean white towel to keep the clothing submerged. Soak for 30 minutes to 1 hour. Wash the clothing normally and then try line-drying it in direct sunlight.
Line-Dry in Sunlight
Hanging clothes in direct sunlight exposes the fabric to ultraviolet rays, which can be very effective at breaking down odor-causing substances that cling to the fabric. You can hang out dry clothes for a day or so before washing them, or line-dry them after washing, even if the fabric comes out of the wash a little fishy. What you don't want to do is dry fishy clothes in the dryer because the high heat can bond the smelly substances to the fabric. Also, the odors can spread to other clothing in the dryer.