1 It also needs to have an area of the pond at least 3 feet deep, 4 - 5 may be better. WATER GARDEN.  A water garden typically contains both goldfish and a variety of aquatic plants. Water gardens in moderate climates usually need for an area of the pond to be at least 2 feet deep. Colder climates require a depth to provide at least 12 to 16 of water below the freeze zone. This topic has a page of its own.
All Navy SEALs must attend and graduate from their rating's 24-week A School known as Basic Underwater Demolition/SEAL (BUD/S) school, a basic parachutist course and then the 26-week SEAL Qualification Training program.
From all my friends who had become SEAL's when I was in, most didn't get into the training program right out of Boot Camp, but instead were accepted into the program after two of three years of active duty. Having been stationed with the seals for several years, the average age seemed to be about 21/22 years. And no, I was not a SEAL. You might be lucky and a current member might respond with a more accurate answer, but in the meantime, I hope this helps.