Well you know what they say about caterpillars. They are very very hungry. I assume this fellow will gladly dine on any and all of your terrarium plants. I think I'd evict him.

Thank you! I was thinking that. I think i see a bite taken from one of the leaves now. Eviction it is!

Moved him to another jar. My son said we had to keep him but in different house. ;)

That's a lovely compromise!

I just got a small closed terrarium the other day

==>> where did you get it from ...???

Update: I am not sure what kind of caterpillar it was/is. I supplied it with fig leaves he ate for many days. Currently I cannot find him. He either became a chrysalis and buried in the soil or became one with the soil.

I got my Terrarium at a cute shop in Whittier, California.

Thanks for the update! I was wondering how it was going.

Looks like an inchworm to me. I'm surprised no one knew what it was. They're the larva of the geometer moth. They eat all the time and can do a lot of damage to foliage.