My apologies if that wasn't your intention, but talking about it being used to clean off animals after an oil spill could give someone the idea that getting soap into the tank isn't something to be concerned about. For the sake of OP and anyone in the future who might stumble across this in a similar situation, I didn't want anyone walking away thinking, "Oh, right, they use Dawn to clean up wildlife after an oil spill, my fish are probably going to be fine," and then find a tank full of dead fish that could have been saved with a large enough water change.Nowhere did I recommend or imply it being ok to use in a aquarium ....