Japanese Name: 鯵【Aji】 English Name: Horse Mackerel

Biology
There are various types in mackerels, but in Japan they usually refer to the jack mackerel. Their characteristic is that they have kind of a spine called zeigo. Mackerels can be easily found in Japan, including some specific brands such as seki mackerel, or saki mackerel.
Stress Reliever
Fish are usually rich in vitamin B2s, but it is rare that they are rich in vitamin B1s, which help to eliminate stress and anxiousness. Vitamin B1s are prone to breaking down once heated. Therefore, it is ideal to consume mackerels as sashimi or sushi.
Good for Bones
Unfortunately, these small mackerels are rarely used for sushi, but they are a good calcium source along with sardines, as their tiny bones are edible.