best predator for beginner???

agree with wippit on the crays. All of mine WILL hunt, but prefer not to.

However, they are endlessly fascinating. In a 30 you could keep 3 easily, and watching them interact is much fun. My kids love 'em.
 
If you need to see stuff get eaten, FW crabs are a good bet. They are easy to maintain for a beginner, but the tank needs to be sealed off well so they do not escape (this really only happens when wires are running out of the tank through an open space). I dont suppose crabs are the same as keeping fish, but its a simple idea that might work.
 
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