Daniel Morrow wrote:
What about using a spray bar in reverse? That way water is brought
into the filter at the same rate as before but distributed over a
large area so no baby fish (as babies might be able to swim out of
the spray bar hole as the suction would be reduced drastically) get
sucked into the filter? Also would be good for weak / ill fish so
they don't get caught in the filter either?

Did you check the EHEIM Pre-Filter 400462?
It has a large open sponge surface of maybe 8cm diameter and therefore the
velocity of the water in the intake is so slow that really any fish can
easily escape. At least as long as the fish is still moving at all.

jue