Two-lines are small sallies being mostly tail. They may be 6"-7" long but they are small. They are also lungless. They absorb their oxygen through their skin. Even though you may find them along streams and creeks(either just off the waters edge or in the water just offshore) they are not totally aquatic. I have found them and their kin(long-tails) many yards from water. Pillbugs and nightcrawlers are TOO big of food items for these sallies. Maybe if the pillbugs 1/16"-1/8" long. But crawlers no way. Maybe tiny red wigglers(red worms or earthworms). To keep well in captivity you would need a good size tank with some land and some flowing water(like a stream or creek), good flat rocks(in water and land) for them to hide under, moist wet peat moss or a peat/sand mix. I kept 2 long-tails in a 55 set up like a stream water edge. It was very heavy and time consuming to clean. You can try a smaller tank but the smaller it is the more difficult it is to similate that type of enviroment. These are just my opinions and experiences with these types of salamanders. If someone keeps these in a 5 gallon tank and are fine, then by all means go for it. 
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"I am all that is Divine, I am all that is Evil.
I am the one who brings forth Death,
On the wings of a Weevil." JSKII