[snatched]

I wouldn't worry about it yet, you just got him and he could still be adjusting to his new tank. Its not uncommon for new fish to not eat for the first day or so and a couple of days without food won't hurt anything.

If you do feed him live fish, its highly suggested that you quarentine them for at least a week (especially if its feeder goldfish, those things are full of nastiness) to make sure they aren't carrying any sort of bacteria or parasites that could be transmitted to your fish. A lot of people find it easiest (and cheapest) to set up a small tank and get a couple of guppies or similar prolific fish. That way you'll have a constant supply of free feeders that you know are clean.

You might want to try some other kind of live food other than fish and see if that entices him to eat.

[richardsville]

So has you jack eaten yet? I have found that if you let them be for a few days their interest in eating comes back with a vengance. South Americans don't usually skip on the meals unless they are really stressed, and coming to a new home from a fish store qualifies. They can go for days with out eating so I wouldn't worry.

Another thing about feeder fish...If you want to feed Jack with live food than be prepared for an increase in his aggressiveness, and if there are any tank mates then they will feel the wrath, if you catch my drift.

[snatched]

If I was keeping GTs, I would probably use Hikari Cichlid pellets as my staple. Hikari foods rock and they are easy to find. I had a packet of the Cichlid Gold and its a nice omnivore mix and it comes in different sizes which is nice.

I don't keep a lot of frozen foods. I mostly feed frozen stuff to my Bettas and you have to thaw out the entire cube (which even several Bettas can't eat) and they tend to be really expensive. The only one I really have experience with is Hikari frozen Krill and everything I fed it to went mad over it.

Freeze dried foods I use a lot. Bloodworms are good for smaller fish, your fish at 3" would probably still do good on them. Fish love them but they're small enough that larger fish don't always recognize them. My larger Goldfish take awhile to find them while the Bettas "hunt" them as they're floating around. Someone gave me a bottle of fd Plankton and I use it on the larger fish, some of my smaller guys can't get it into their mouth too well. The Goldfish love it though. I haven't used fd Shrimp but thats usually a staple food for larger Cichlids, since it provides a lot of roughage to their diet. I have fd Tubifex worms as well and I don't care for them. They're pressed into those little cubes and I have to soak them and pull them apart a little bit before any of the fish will eat them. Even then the fish don't seem crazy about them. Plus when the cube breaks up you're stuck with a bunch of tiny ass worms floating around your tank and it makes a mess if nothing is eatting them.

Really, most Cichlids will eat anything (including Cories) even if they aren't supposed to. I always had problems getting algae discs to my Pleco because my Mbuna would steal them. As long as you stick to a few high quality staple foods you should be alright.

Being omnivores, you probably want to include some veggies. I don't know how well GTs take to veggies but every fish I have ever kept (from herbivore Platies to carnivore Bettas) loves peas. I don't know why but nothing makes them happier than throwing in some lightly cooked de-shelled peas. It creates a little riot as they all fight over them. I buy those giant frozen bags and pop some in the microwave for a few seconds, pop them out of their shells, and they're ready to go. They keep their digestive systems clean too, they're used as a remedy for swimbladder problems and since I've started feeding them I've never had any problems. A lot of people use Zuchini (or however the hell you spell it) and I drop some in when its in the house but usually I am lazy and just feed peas which the fish like better anyways. Sometimes I feed other things, lightly boiled greens, seaweed, etc but mostly I stick to the peas.