best predator for beginner???

Nothing's wrong with them, I just don't think are good for abeginner setup. They tend to be tough to get eating prepared foods, and providing quality, appropriate live foods is tough for beginners. In a 30, they will go after pretty much anything that's added with them, and may target each other if not fed properly. Not a tank that has a high chance of success, IMO.
 
Neolamprologus leleupi readily eat smaller fish and max our at 4-5'' (males). Not the most glamorous, but they are very pretty and seem fairly hardy as long as they are kept in good water conditions and hard alkaline water.
 
wouldnt a full grown african CLAWED frog eat small feeders.
I know this is a fish forum but you could fit an aquatic turtle in that tank, they eat feeder goldfish or guppies, and your son might like him. Just do some reading on the turtles.
 
if I were you I would gowith one or two convicts they can live in a thirty and are oneof the meanest small fish you can get I have one that I got about two years ago and sha has tomentedor killed every thing that has been in her tank including an oscar that was three times her size. They are lso great for a beginner because they are very cheap and very easy to care for
 
if you want something that will eat the occassional fish then try a rope fish...they eat any sinking food though, and usually will ignore your fish...but they are really cool and kids tend to love their snake like appearence. One would do well in a tank your size.

Piranha are out for stated reasons (skittish, big schools, get large fast, overrated, but they are very easy to keep one of the hardiest fish I've ever kept in fact!, they also eat flake food)

african cichlids are just mean fish...very territorial and can't be kept with anything but other aggressive fish (in my experience)

arrowana would be great but they grow quickly and in one year would out grow your tank.

butterfly fish are just a little on the boring side for my taste

clown knifes are nice and one would do well in a tank of your size for a few years before it got to big

then of course you have the uber eater/agressives like oscars etc...they can be fun...but they will wreak havoc on any kinda decorations (IME)
 
As the proud of of a 7in long crayfish, I wouldn't suggest them as predators, because they're not the most successful thing out there. They're primarily scavengers, and snagging a live fish is rarity. Only saw it happen once, he attacked the pleco (which got away on it's own). The pleco is now in a different tank, incedentally.

That being said, he did eat a grown male guppy a few days ago, based on its disappearance. But I still have a male and 10 babies in there which he doesn't actively hunt, he just waits for one to come near.
 
We haven't added any other fish yet.The tank does seem to be doin well.When he is ready we will do some more looking.Then I'll probably be back on here asking opinions again.So far the fish we do have stay hid most of the time.
 
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