I recently finished a sweet little fish amigurumi. The pattern I followed was Fancy Goldfish Amigurumi, a free pattern by Kate Wood. She did an excellent job with shaping and with the texture of the fins. The pattern was easy to follow and the finished object is adorable. The one thing I will mention is that, though the pattern doesn't state it directly, you should be sure to crochet into the chain stitches on the tail fin. Overall a quick, enjoyable project.
I used leftover Knit Picks Chroma Fingering from a shawl I made, along with a 2.75mm crochet hook. The slow striping of the yarn was totally perfect for this project. Here's my fishy. What should his name be?