Murphy's law strikes again!

[mrhasan]

Maybe those pills are exothermic and when dropped in water heats up the water?

Checklist by pet stores:

Improper packaging (check)
Wrong address (check)
Expired product (check)
(And newly introduced)
Dog product instead of fish (check)

That's some kind of propaganda I guess. Its throwing a message like "hey look, the dog products are more appealing than a fish tank heater; get dogs, throw away the tanks".