Hi ThingThing. (New screen name for Jen of SoCalDiscus) Thanks for the response. Well my little kid has been joined by another one, and they are indeed growing like monsters. I would guess they're 9 inches now, and they are darkening up. I believe that they we're juvenile nigers. As for the video link, I have seen that before... in fact I have seen the entire series! They're awesome. The fish you pointed out is a irwini meglodoras, which I have. He also is growing at a good clip, and we are in the process of upgrading to a larger tank, a 180 gal with a 100 gal sump (which will act as a refugium, wet/dry, and second tank).
Anyways, thanks again for responding! I'll have to get some new picks up.
Oh, and as for knife fish, I'll have to get up a post about our zebra knifes (knives?) how do you pluralize this for the name of the fish...