JP Fish2：魚

The app also focuses on a single Kanji letter. All letters that you practice on JP Fish app mean fish though; at this time, some letters mean marine mammals, such as whale and killer whale.
Although I mentioned on JP Fish app, here is a tip that hopefully would help you to get to used to learn Kanji letter. Some Kanji letters consist of basic Kanji letters. As I mentioned "Some", This rule does not always fall into all Kanji letters but you may get an idea. Here is an example. There is a Kanji letter that means a parent. This Kanji letter consists of three basic Kanji letters, such as meaning of "look" and "stand" and "tree". You might wonder why "parent" relates to "look" and "stand" and "tree". As far as I know, a parent is supposed to look a children standing on the tree, that is why. In the same manner, Kanji letters you are going to practice on the JP Fish app include a basic Kanji letter meaning of fish.
This is a basic Kanji letter meaning of fish.
[魚]
Here are a few example.
This is a Kanji letter meaning of a killer whale.
[鯱]
As you see, this letter includes a fish letter on the left side. On the right side Kanji letter means "Tiger". I am not really sure why a letter of "Tiger" is included though; it is possibly based on the fact that it is described as a violent-tempered creature, like Tiger.
This is a Kanji letter meaning of a full-grown gray mullet.
[鮱]
As you see, this letter also includes a fish letter on the left side. On the right side Kanji letter means "grow old". In this case, it may be based on the fact that Gray mullet becomes Full-grown gray mullet as time passes.
This is a Kanji letter meaning of a octopus.
[鮹]
Although it is not a fish, this letter interestingly includes a fish letter on the left side as well. Believe it or not, we use this letter as a meaning of an octopus.
I wish I could explain all Kanji letters though; I am afraid that I am not a professional person. I hope that you would get an idea about how Kanji letters are made and you may interest in some letters in this app. Perhaps, some letters you practice in the app might come in handy, when you go to a sushi bar in Japan someday.
Enjoy writing Japanese letters!