Instructions
Search for fish, snails or other animals that may have died in the tank. Look beneath gravel and decorations for carcasses. Filters may also contain animal parts.
Check your tank's filter, which may begin to smell if you haven't performed its regular maintenance. Replace 10 to 15 percent of the tank's water every two weeks.
Remove uneaten food from the tank. Discard uneaten food 10 minutes after feeding your fish to prevent the food from rotting.
Compare the population of your tank to its recommended population size. Overpopulated tanks overload the filter with more waste than it can process.
How to Fix Bad Fish Tank Smell
Fish tanks develop odors for a variety of reasons. If you perform regular maintenance of your tank's water and filter, the problem may be a dead fish or unhealthy fish refusing to eat. Whatever the reason, fouls smells emanating from your fish tank indicate that its environment is unhealthy and requires your attention. Untreated odors typically develop into an invasion of unhealthy organisms that will kill the fish in your aquarium.