OK, thanks for clarifying, it is what I thought you initially described.
Surface fish will have issues here, and the only way to rectify this is by changing the filter return spray bar(s). There is actually another benefit to doing this that I will explain.
Fish that have evolved to live in quiet water (such as hatchetfish mentioned, gourami, etc) do not appreciate a rough surface to the water. The fish must exert a fair bit of energy fighting this, and it is 24/7, so this at best will weaken the fish over time because they are simply not made for this.
The other thing is that fish from streams, creeks and rivers expect a current downstream. In an aquarium that is long as here, it is best to have the filter intake at one end and the filter return at the opposite end. Not only does this create a natural flow for the fish, it also improves water movement within the aquarium and in a natural way. Fish that want to be in the stronger current can be, but they also have the option of avoiding this in the quieter areas.
When I had my 5-foot 115g tank set up as an Amazonian stream, it was very instructive to observe where the various species positioned themselves almost permanently. Many remained at the quieter half, much as they would in their habitat. The myth about this or that species liking a current was shown to be just that, a myth. Given the option, the fish avoid it because it is too energy-driven and that means stress which further weakens fish.