No. The faster moving pelagic/surface dwelling species of fish are more likely to be streamlined.
Sharks, Tuna, Mackerels, and Marlins are all examples of Streamlined body shape fishes.
because seals need to hunt for fish, and to swim faster, they have evolved so that their body has changed and became streamlined. having streamlined bodies makes seals swim faster and can change direction better, making it a more efficient hunter and some diarrhoea
It was obvious he'd merely streamlined my report! Won't today's jets fly faster if they become more streamlined? This team will operate much more efficiently after I've streamlined it.
fish
There is more resistance in water but fast fish are more streamlined than fast animals. A swordfish is faster than a cheetah.
fish need to be more streamlined than land mammals because they need to be able to stream quickly through water. They need to be able to do this for many reasons such as to either catch their prey (if they are large carniverous fish) or escape from their predator.
Pointed tails help make elephants more streamlined and aerodynamic.
A. Yes
Probably not. The female is more streamlined and designed for a fast get away. She usually has to flee from any marauding male who may decide to 'have' her and/or kill her.
To help them swim with less fluid resistence, thus with less energy loss, which is one important driving factor in evolution. Streamlined bodies usually cause less turbulance and so are more "aerodynamic" in water or in any other fluid, such as air.
I suggest that you learn more about your fish in your aquarium. One of your fish might be a bottom sucker which means that they eat all of the dirt on the side or bottom of your tank. If one of your fish are bottom suckers, that's probably the reason why your aquarium is clean. If none of your fish are bottom suckers, than somebody must be secretly cleaning your tank for you.
Well If you mean like preserved as in fossilized shell fish (clams and lobsters and such) have the highest fossilization record. The are more likely to be traped in sand, or mud at the bottom of the ocean. But this is just a quick guess