I guess a few weeks would be nice. I would rather they get on in harmony. Putting fish in there that enevitbly get eaten is like stranding a person at sea.
If the snails are larger than the puffer then no. The puffer may injure or kill it, but not eat. Vice versa the snail might eat the puffer if large enough.
Fair enough. It's be cool to make like a waterfall in a tank and have like a pond at the bottom. Then you'd be able to see the loaches climb. If only they liked slow moving rivers...
I've heard of people using holiday feeder blocks or bird cuttlebone? Not sure on the cuttlebone though. Also if you add crushed up sea shells coral etc. It will make the shells turn less white. Sorry for late reply!
Squirt
Hmm I'm 15. I mean I have a pool that hardly gets used or I live a minute away from the beach so is swimming good for endurance? Also it would build a little upper body strength at the same time, right?