When I brought my baby jar home (at 2.5") on X'mas Eve 2008 and put him in a 10g long with HOB filter, I made sure every hole and crack on the tank was closed out. I used paper cardboard cut to the sizes needed and taped on to plug them holes. Just a reference for the next time... Baby aros are cute so I'd start with raising one from that size again. Good luck the next time!