Thanks for your response, Nooboon. I will be more careful in my purchases with your advice in mind.

Hi Lloyd-Your knifefish sound great at 8-10 inches. I am hoping my poor guy reaches a good size. The last one I had for 6 yrs. I made a terrible mistake treating a sick angel with [unbeknownst to me] a knifefish incompatible medication. I was sick about it. Hindsight is 20/20- why didn't I just quarantine the ill one?
My tank is kept in semi-shadow for my angels [picked from ones I bred] & is well planted. "Curled-up Knifefish" has staked out a tree fern stump covered in java fern. With all the plants/ dmmer light, he's social during the day [actually, he's my best pal whenever it looks like food is involved ] I always heard no to groups of knifefish, but I would love to try another [No more PetSmart !] at your suggestion. So far, this sweetie has been very peaceful to tank mates, but he is still so young. Thanks again! Rose