In fish I would much rather be applying pressure, but Chant could see play instead of stifle in some meta games. If you don't see a lot of control, chant could be good as long as you have enough white to support it. It can act the same as a stifle against combo, except it can't get duressed away because you can play it at upkeep.

[begin irritable rant] Okay, now seriously here. Explain why one copy might benefit this deck. What will it help against? Might more than one work? What would you recommend removing? I know that some of us will know why it's good, but other people, like the new and inexperienced, might not understand why. [end irritable rant]

If the Hatchlings are to be replaced it has o be annother blue creature to keep the number of blue cards total. I also should have a cc of 2 because of the Vial. I can't think of a 2-power, 2-cc blue creature with flying besides Gaea's Skyfolk, which was already mentioned above. It ita harder than Hatchlings, but lacks their diruotive element. Hopefully I'll find some time to test them both during the next week.