The water is more likely sucking through those holes [tank divider for acrylic tanks on a central system] to go to their filtration and died and got sucked to the wall . From the condition of the wall , guessing they don`t do much maintenance . Run far , far away from that place !
oh that is terrible ! poor fishies .our lfs in my town sells dyed fish and has a shark in a tiny tank where it cant turn around so we get all our stuff online or in a town 45 minutes away .