Fishes are nice to have and good to eat. By that I mean I have two at home and named them Hardy Heron(new Ubuntu release). You ask how can a fish be named Heron? I say why not!
Trying to capture them in spirit using trellis stitch was an enjoyable experience. Between the two I like the latter.
Learning: Never try trellis stitch with a very thin thread. It tests your patience and the lovely texture of the stitch does not show properly. A perle 8 is ideal as the stitches move really fast leading to instant gratification and the look-and-feel effect is great.
Next, a dragonfly would be a good option to try. The net like effect of trellis stitch can accentuate its wings well.