i ask because i have a hydor koralia circulation pump and when i turn it on it seems as if there is too much flow in the water, my fish can't swim near it as it pushes them away and poor little horshoe crab ends up at the other end of the tank from all the force, other than this my corals seem fine with slightly more movement.
The current issue will depend on structure in the tank. Some fish do like quieter water, but no shallow ocean water is ever very quiet. If your rock is laid out so that there are areas with relatively low current where a fish could rest if it wanted to, they should be fine.
You know horseshoe crabs can grow to 2 feet long right?