"One of best ways to distinguish the sex of a trout is to examine the mouth. Female trout all have a short rounded nose or upper jaw, while male trout have a more elongated snout. If your trout has a lower jaw with a kype, it’s a male for sure. Although the mouth of a female trout will grow larger as it ages and increases in size, the mouth will never grow a kype (hooked lower jaw). Upon becoming sexually mature, male trout will begin to grow a pronounced kype. At first, it will just be a tell-tale sign, but as a male trout ages, its kype will become more pronounced"
Maybe one of each sex?