Speaking of the Reflecting Pool...

[wyn borkins]

2. Catfish Might Prove Useful

Your idea might not be so fishy after all. In a similar manner, a herd of goats has often been used to clear hilly (ground) areas of "green" overgrowth.

However, with all the newly added chemicals to the reflecting pool, those catfish would have difficulty surviving long enough to effectively clear the overgrown algae.

Of Related Interest (from the Internet):

Many fish and invertebrates are utilized to naturally clean up soft film, hair, and green algae in fish tanks and ponds:

Fish: Siamese Algae Eaters, Otocinclus Catfish, Bristlenose Plecos, and Molly fish are highly effective in freshwater. In ponds, Koi, Goldfish, and Grass Carp are common grazers.

Invertebrates: Amano Shrimp and Nerite Snails are widely considered among the best cleanup crews because they consume large amounts of algae without multiplying out of control.