<Tr> <Td_colspan="7"> When Cam comes into contact with water from the Moon Pool, he absorbs the water into his body and gains the ability to control water . The water also enhances Cam's swimming and earns him a shot in the school swim team trials . Zac, Evie, and Erik are worried about what effects the Moon Pool water will have on Cam and tries to convince him not to swim but Cam does not listen . Their worries are proven correct when the water soon begins to have unpredictable effects . The mermaids must figure out how to remove the Moon Pool water from Cam's body before he swims in the trials . </Td> </Tr> <Tr> <Th> 42 </Th> <Td> 16 </Td> <Td> "First Date" </Td> <Td> Grant Brown </Td> <Td> Max Dann </Td> <Td> 31 May 2015 (2015 - 05 - 31) </Td> <Td> 29 May 2015 </Td> </Tr> <Tr> <Td_colspan="7"> Erik finds a pearl and gives it to Ondina as a gift . When Erik says he wishes he could find more to make a bracelet for her, Ondina sneaks him into Rita's grotto and uses a duplication spell to create more pearls . Poseidon is in the room, and Erik takes an immediate liking to him . Things soon get out of hand when Ondina accidentally spills some magic powder on Erik, turning him into a second Poseidon . Ondina makes things worse when she tries to reverse the spell and inadvertently creates two more Poseidons for a total of four cats . When three of the cats wander off, the girls must find them, figure out which cat is Erik, and reverse the spell before Erik permanently becomes a cat . </Td> </Tr> <Tr> <Th> 43 </Th> <Td> 17 </Td> <Td> "The Merman Code" </Td> <Td> Grant Brown </Td> <Td> Sam Carroll </Td> <Td> 7 June 2015 (2015 - 06 - 07) </Td> <Td> 29 May 2015 </Td> </Tr>

When does zac find out they're mermaids