Overflow question

[Tarolisol]

Ok so what i am envisioning is in my overflows where the bulkhead are attach a pipe to raise the level of water in the overflow and add a strainer onto the top of the pipe. I want to have some water in the overflow incase a fish does make it into the overflow thats why i want to raise the waterlevel in it. Also i would do a standpipe or durso or somthing but i have a return line in the overflows so theres not much room left.