Yay! Was very sorry to hear that you also lost Jack but great that the new kids are doing well! I really like seeing a mix of ages together as their interactions can be quite interesting.
Odd Seahorse story... was at Seahorse Aquarium yesterday and wondering why some of the seahorses had white patches. Apparently the starry blenny in the tank had been "cleaning" them - much to their chagrin. So... make sure you keep the kids away from any hungry algae blennies!