3.5" maybe - doubt he's 4 inches - I can measure him tonight. The tank lights are off right now. He's definitely gotten thicker but not a notable amount longer. Supposedly they typically get to about 6" typical, 8" occasional. Slow grower in my experience (got him at around 2" almost 1.5 years ago) - and this guy's a little pig.
But it’s a good point to note that may be a 6 inch version of this would eat a rummy nose? I don’t know that I trust something as small as an endler but… this guy seems way more interested in things like worms. I don’t think I would try any expensive shrimp with them.
I'd say possibly, and maybe more as they got bigger? I have sand, mine mainly digs around in the sand to look for snails. For the most part, he prefers to hide and hang out under leaf litter, branches, plant leaves etc. I've never seen him bury himself like other eels. Not sure if that's normal for the species. I have a bunch of plants including crypts and he doesn't bother them at all, but my plants are well-established so that helps. I don't have any carpet plants per se.
I also have a lot of floating plants, which keeps the light dimmer so maybe he doesn't see the need as much since there's so much cover otherwise? This little tank is kind of a jungle - I kind of let it grow wild with occasional cleaning off of the fuzzies that grow on my wood, etc.
Still love the little guy. Very peaceful, curious, out and about a lot, and a big food beggar. He doesn't bother a soul, just does his thing. He'll eat out of my fingers, too.
I took a photo a couple of weeks ago. You can kind of see his mouth. This is next to a chunk of frozen cube. Maybe I see it as small because I'm used to bichirs?
He's always been with other fish and doesn't even seem to notice them. Eats right alongside the cories and the ram, etc.
EDIT - image doesn't want to attach. Will try again in a minute.