Phineas and Milo: Christmas Crossover

act 1
when phineas and ferb accidently use their shrink way on christmas eve in bud's pet store and they all become fishes [except perry]and they meet mi lo and oscar and fish phineas asks if their is a way out but milo and oscar tells the new fish group that the only way out and back to the shrinking device is to have the water fuels