Aqua Primates, or A-Primes for short, are a species of brine shrimp (specifically, Artemia salina x nyos) which are frequently sold as a novelty pet. Although the packaging they are sold in depicts the A-Primes engaging in such activities as crowning their queen, fighting robots, and designing websites; in actuality, the nearly-microscopic creatures can do only one trick: move towards a light source. While vacationing in Hawaii, Phineas and Ferb purchased their own A-Primes and grew them to a much larger size with the help of some growth elixir, which made them much more entertaining- although they still enjoyed moving towards light sources more than anything else.