Whatever you do, don’t put any plecos in!
Turns out they eat the plants.
I found this out the hard way when my breeding colony of BN plecos wiped out the 10 plant jungle which had taken a year to grow!
Off to buy them on Wednesday along with the chocolate for the photo competition.
First accidental breeding:
As soon as the fish event is over, my Assassin snails are gone!
(Unless they're fun)
I think what you really need to take into count is the weight, but besides that (if you plan to drill holes) I would take a relatively thin piece no more than .5 cm wide (a fifth of an inch)
Maybe try attaching weights to it if you want the quick solution, but normally it sorts itself out within a week.
I guess it could be oxygen formed by bacteria making it float?