Moving only a block away??? hmmmm. If it were me, and I'm not the guru like
Ingrid or Geezer,

I would hand catch them (not a net) and move them into a bucket of fresh, day
old water... This means you fill a bucket the day before and let it age before
you put the loved ones in... Make sure you match the water temperature. Get
two of those 5 gal buckets from Home Depot. They work nicely, and then when
you are done, you can return them for a refund. ; ) While they are in the
bucket, have an airstone in it for air, and put a couple of their fave toys in
- but not so many it takes up the whole thing. For us, we put one of their PVC
tubes in to hide or play... Move the fish to the other awaiting bucket every
day. It's a real pain to swap buckets daily, but they will stay well until
they finish "moving" too...