it's been a long time, since I've had a fish "go over the wall", even though, only a few of my tanks are covered...most open tanks, have a hedge of plants growing above any open sides, so a fish would either have to climb through a jungle, or really go airborne to not get bounced back into the tank... many of these plants go 18 inches over the top of the aquariums... the work area behind my tanks, just has the poured concrete basement walls, and floor, so I'm attaching a stainless steel strip, that sticks out from the wall 1/4 inch, to hang the pots on, while I work on tanks, or to groom up the plants, if the roots or tops need trimming... I can place one of my tank dedicated dish pans on the floor below to catch any water that drips from the pot... some pots that have vines, will have to stay in place, as several vines are more than 20 feet long, and all entwined above the tanks, but the Peace lilies, many need a trimming, and the lucky bamboo, are along the backs of the tanks, which is where I service these tanks... I used to just clip them on to the outside of my 10 gallon holding tanks, but those have become a place for extra plants, and they are now too plant busy, to hang anymore temporarily... this picture I took last night, shows a Peace lily badly in need of a haircut