if it has a weird odor, its BGA (blue green algae) if you read up on this stuff you will soon find out that it is actually a cyanobacteria and not an algae at all. Nothing in the world eats it so bad news there but its an unharmful bacteria to your fish so good news there. Ethromycin is the only proven medicine to rid of this bacteria and is fairly gentle on your fish, not sure about inverts though. this stuff forms as a result of poor water flow or poor oxygenation and stale stagnant water. Once you rid of it with the medication or by manual means (it sucks up fairly easy with an airline hose siphon) add a bubbler or two to keep it from coming back. Good luck, everyone has dealt with this stinky stuff once or twice it seems.