If your glasses smell fishy, it's possible all of your dishes have the same smell. It can be more apparent on glassware because of the proximity of a drinking glass to your nose and mouth when using it. A fishy smell in the dishwasher is a common problem caused by the buildup of food particles.
Leftover food that's stuck in the dishwasher can eventually rot and cause a fishy, musty or rotten smell on your dishes, even after running them through a cleaning cycle. Most food particles should rinse off the dishes and drain out of the dishwasher, but the accumulation of larger pieces of food can block the filter and cause a fishy smell.
Remove the filter from the dishwasher and clean it thoroughly, using a stiff scrub brush, soap and hot water. Instructions on how to remove the dishwasher filter vary by make and model, so check the manual for your dishwasher to ensure you're removing and replacing the filter correctly. Manuals can often be found online.
The inside of the dishwasher may smell fishy despite cleaning the filter and need to be cleaned. Mix 1 qt. of water, 1/4 cup of bleach and 2 tbsp. of dish soap together. Use this mixture to scrub the interior of the dishwasher, including gaskets, shelves and walls. Rinse the mixture out of the dishwasher by running an empty cycle at the hottest temperature available.
Rinse dishes before putting them in the dishwasher or at the very least scrape off any large pieces of food so they won't clog the dishwasher's drainage system. Continue using dishwasher cleaning products and soap to prevent the buildup of food particles that lead to a fishy smell on your glasses and other dishware.