Is Bleach Safe to Use in an Aquarium? The answer is yes. When used in the correct concentration, bleach can be used to clean an aquarium. We recommend mainly using bleach when completely cleaning out an aquarium. This may be when you have had a fish pass in this aquarium or it has been in storage for some time. Bleach should be used when boiling is not effective. Bleach is … [Read more...] about How to Disinfect (Sanitize) Your Aquarium with Bleach