When I use a net I usually go with a fine white mesh ( not quite as fine as brine shrimp net ) and put the seam on the "outside" of the net. The finer mesh seems to support the fish better with less damage. Also, I have no had any issues with corys or discus getting spines stuck in that kind of netting. I don't have any of the other cats or plecos so your mileage may vary as it were. Getting the fish into a submerged container is better but often just not practical.