I read here somewhere that Hellfish swim like boldurs on stereoids..
...I'm also relatively sure that crabs move similarly to green seedkins and drag the line for about 4 swipes (times you can pull at the line)
Racerfish are quick ,they gots only 1 swipe interval before changing directions.
Balloon fishes are very easy ,they move like weak seedkins.
Jellies move like weak trouts. Ironjaws are like weak boldurs/hellfish.
All the new fishies in bassken seem to me like weakened versions of the older ones..
...I know its not too specific but I hope it helps somewhat :3