|MadSci Network: Biophysics|
I do not have a comprehensive answer to your question as the answer is quite complex. There are, broadly, four categories of fish; "Sneakers", such as eels, are capable only of slow speeds but possess some staying power;"Stayers", like grayling, can swim quite fast over long periods;"Sprinters" can generate fast bursts of speed (e.g. pike); and "Crawlers" are sluggish swimmers, although they can accelerate slightly (bream, for example).
In my view, the motor efficiency generally increases with speed at the cost of manoverability. However I will refer you to an article written for Scientific American in 1995 which I hope gives some insight into the relative efficiencies of the movement of different types of fish.
An efficient swimming machine http://web.mit.edu/towtank/www/Papers/efficient- swimming.pdf
Another good article
Review of Fish Swimming Modes for Aquatic Locomotion can be found at http://www.societyofrobots.com/robottheory/Review_of_Fish_Swimming _Modes
and if you can access journals then
Swimming efficiency and the influence of morphology on swimming costs in fishes http://www.sp ringerlink.com/content/r512550v45100842/ is interesting.
Also have a look at
Optimal Swimming Speed in Head Currents and Effects on Distance Movement of Winter-Migrating Fish http://www.ncb i.nlm.nih.gov/pmc/articles/PMC2359855/
Sean Hunt Jan 2010
Try the links in the MadSci Library for more information on Biophysics.