If you were thinking of using a gravity fed irrigation system, I'd be concerned about fish gunk blocking the holes. As it is, my water can gets blocked and I need to clean the perforations.
The popular thing it seems these days is to conserve water by using sub irrigation techniques. You put the fish water into a reservoir under the plant roots and the soil absorbs by capillary action to allow the roots access.
This is a planter box from the warehouse purchased during a special On the right front corner I have a black pipe that goes to the reservoir at the bottom to feed the fish water. Irrigation from the top is avoided to prevent nutrients washing out of the soil into the reservoir, and to avoid watering weeds and compacting the soil. These days I would use an inverted plastic drink bottle with a flap cut from the bottom of the bottle as a natural funnel, and since the bottom remains there it prevents mozzies from breeding inside the water. This design has a hole to empty the water but no overflow. I drilled one myself so that the plants don't drown when it rains. Unfortunately I hadn't banked on the strong December Wgton wind which broke a few of these beans .. some of which I have cellotaped back together