Here's a mistake I keep repeating, trying to add another fish in with my big guys. Apparently ther not taking ANY applications for another tank mate. Hopefully fifth time will be a charm.
Years ago i bought about 30 baby RBP and had them in my 30G
After a few days i went to siphon the substrate and do a w/c.
i stepped away from the tank for a few minutes talking on the phone. when i come back i have only 10 fish left with little water in the tank, water all over the floor and the rest stuck at the top of the siphon hose dead.
I laid down a brand new 55gal tank on its side to remove a sticker from the bottom of the tank and laid it flat on a marble in the living room....cracked the whole side in to hundreds of pieces...