Ok. IMO, you could move them if you wanted to. You just have to be very careful when you catch them. If you would like to keep them in the tank there is always a chance they could get hurt or eaten. Don't be afraid to clean your tank! They will move out of the way when you start to siphon. Just check the bucket when your done to make sure none of them have ended up in it. I have ones that are about a month old (and an inch long). I moved them from their 10g to a 29 gallon and only lost one (due to my hurrying along, instead of being patient). But I learned real quick that they may be quick ones but if you can corner them they will swim straight into the fish net. Hope that helps. Good luck.