Sounds very cool , one of my SAL was about 4 inches and thin as a pencil when I bought it 1.5 years ago. I kept mine for months in a critter keeper with a few inches of water , bare bottom and a few plant stems. I changed the water out every time I fed it since there was no filteration. I personaly did not feel comfortable in putting it in a small aquarium with running filter, I felt with the lack of size and strength, it was too fragile. I like to take that extra step and making sure the fish is eating , gaining weight , no stress from too much current ,etc which is another reason I kept mine in a critter keeper. At 1 1/2 or 2 inches , I can only imagine they are about as strong as European Nightcrawlers so I would go with the 2-5 gallon container/tank route with no current. Perhaps I'm way too careful and I'm sure there are other ways to baby/juvie lungfish husbandry but it's always worked for me. Good luck and please show pictures. I would imagine these still have gills and maybe look Axolotlish ...