Anwhistle Aquatics is first mentioned in The Grim Grotto.
Anwhistle Aquatics, a marine research and rhetorical advice center, was moderated by Gregor Anwhistle, an ichthyologist and Josephine Anwhistle's brother in law. An article from the Daily Punctilio states that Anwhistle Aquatics was burned down by Fernald, although Snicket discloses to the reader that Captain Widdershins also participated in the center's destruction.
One of Anwhistle Aquatics's roles was to investigate the Medusoid Mycelium. However, when it was burnt down, the Gorgonian Grotto was filled with the deadly fungus that was left behind. The centre also trained salmon under the Voluntary Fish Domestication program, until the entire fleet was seized by Café Salmonella.
It is implied that the sugar bowl once found its way to Anwhistle Aquatics, but had been removed by the time the Baudelaires reached the Gorgonian Grotto.
It is also implied in the section of The Wide Window describing Lemony Snicket that he was working there at the time, as it mentions that he worked at a 'rhetorical advice centre'.