What size breeder box are u gonna use? I imagine the medium would be fine for the rimless. Sine I have nematodes these boxes usually become a haven for them so I tear them down every time. Also I think they take away from the purpose if a rimless tank xD
I've got two mediums but was going to pick up a large at some point. The tank this is going on the side of is a 3 gallon Kritter Keeper type thing (same basic thing, different brand) so no way am I putting it on there as far as letting the weight of the breeder pull on that tank. I'll have a box under that one for sure. For the Mr Aqua 12G rimless it would probably be fine on that one, but still not positive.