I started in the hobby with a freshwater stingray. At thet time, I knew nothing and were guided by the LFS clerck (who knows nothing).
Watching him chase and eat feeder guppies gave me that "powerful" feeling, and I became in love with predators.
Now I have in my tank 2 rays, 1 clown knife and one albino senegalus (¿?)bichir. I had a reedfish (RIP).
Space wise, I've had my bichir for about 10 days, and he is doing well in the 235 gallon tank. He is 4" long only, but has little problem finding food and competing with the other fish. He likes to hide in the ornamental caves and rest in the plants leaves. However, sometimes you can see him free swimming around the tank.
By now, I feed him with tubifex worms and chopped earthworms. I've thrown feeder guppies into the tank, but the knife eats them all in a matter of seconds, leaving nothing to the others.