Knifefish?

[cer]

What is the smallest type of knifefish? Is it compatible with small tetras?

[toddnbecka]

The smallest species suitable for aquariums is the african knife. There are a number of species from the Amazon, but they seldom live long in aquariums.
Africans are compatible with anything too large to eat, but need at least a 75 gallon tank.

[aquakid]

centipede knifefish grow to 8 inches, although species tanks are recommended. they are very rare.

[cocoa_pleco]

yep, african knifes are the smallest. i had one in my 90g but he went MIA a long time ago

[Oscar_freak12321]

African Knife fish get to only 8", but the Black ghost knife gets to 1' and they both have a very peaceful temperament. The upside of the bgk is that it adjusts much more quickly than the African. it's really up to you.