Here are all four, finished and ready to swim. Elder Daughter did the one at the upper left, with the lighter orange fins and tail.
The two new ones are the dark green fish that looks something like a cross between an athletic sock and a trout, and the pastel fish, with its pattern of stranded scales. Dark green and pastel will be wriggling their way to my nephew and niece in Buffalo by Monday.
If you’re working your own fish hat and want to do stranded scales, here’s my six-stitch repeat. It fits nicely into the 90 stitches around segment of the body, and the clever can probably work it into the decreased sections as the body slims down towards the tail, which are also multiples of six. Click on the thumbnail below for the full size version.
String-Or-Nothing 
You tempt me even more to make these… thanks for including the stranded repeat!
Those fish are so fun. I may have to try that pattern.