In recent years conventional tags such as anchor, jaw and disk tags have been improved. Genetic tags or markers have also been developed. These tags are usually implanted into cartilaginous tissue in the fish's head and read with the aid of a microscope. Because these tags are small and embedded in a fish, they are usually not easily seen with the naked eye. A magnetic detector or wand is used to scan fish for the presence of a coded wire tag.
Biologists often give fish with a coded wire tag an additional mark, such as a fin clip.
For several years, the Game and Fish Department has tagged young salmon with coded-wire as an integral part of its Sakakawea salmon management program. On the Missouri River System downstream of North Dakota, adult and hatchery-reared YOY paddlefish are being tagged with coded wire as part of a research and management program involving several state and federal fisheries agencies. To date, virtually all of these tagged paddlefish are hatchery-reared. Only in upper Lake Sakakawea has it been possible to capture and tag large numbers of wild, naturally-reproduced YOY paddlefish. When young paddlefish reach about five inches in length, their paddles have apparently developed to a large enough size to force them to the surface when startled.