Hey, I don't know how dead this topic is, but can I make a suggestion?
The first one is about feeding saltwater fish to saltwater fish. It does make sense since that is what they eat in the wild. Siversides (Family Atherinidae) are a kinda "minnow" that lives in shallow waters nearshore. They're actually pretty tasty, like anchovies or sardines. But it is a very quick way to add a saltwater disease to your tank or fish unless you have a q-tank for the live foods before you feed. Freshwater disease from feeder goldfish won't have a chance to get a hold in a marine aquarium the way it might wipe out an oscar or arrowanna. From personal experience, I know feeder vats are not the cleanest, healthiest places in the world. And the local bait shop is probably not a clean source of live food either. So giving live foods a q-period, giving a preventative medication, and gut loading them is the best way to prevent disease spread and dead fishies.
So what I do for my small-mouthed predators like dwarf lionfish, marine bettas, and cardnials, is breed black mollies. Yup, those fish that always seem to get that white skin fungus and die in freshwater communities thrive in a saltwater environment. The ones I have are in a ten gallon tank kept at 16ppt salinity and they are thriving like you would not believe. I keep three nice sized sailfin males with half a dozen females, and they're always having broods. I grow them out to various sizes, switch studs and dams around, and viola, a renewable food source that will survive in the marine tank without going blub blub at the surface the way throwing in feeder goldfish might, thus discouraging your predator from being hungry. The fish are nutritious because I know I feed them before they become lunch. Malnourished feeders mean malnourished fishies! I also know they are parasite and disease free because I can monitor them personally rather than take the chance on the feeder vats.
The perfect thing for that spare tank lying around. When you're keeping marine fish, you need a spare tank for everything ;D
Food on a -plastic- fork is also a good way, although I must admit, I think that chopstick method has got lots of class
. Some predators are movement-sight oriented, and the food has to be wiggled in front of their face for them to be hungry.
I find this method the best for morays, hawkfish, and sharks. Predators you want to be -quite- sure are fed before they feed on tankmates. You can actually train a fish to target to a particular spot in the tank to get fed. Takes patience, but you'll be sure there isn't a hunk of something rotting behind a rock and making all sorts of messies.
Calimari squid is good, mussle and clam, and shrimp. I always buy fresh foods prepared for human consumption, so I know it is good stuff (and hell, I like sushi just as much as my fishies). Wash and peel shells first. And I use small chunks and fish. I did have the experiance of a dwarf lionfish choaking to death on a feeder it nabbed that was meant for a larger tankmate. Talk about feeling like a murderer! I cried all night. I'd rather take my time to feed smaller chunks than be rushed and have the above happen again.
Don't used canned or processed fish, like starkiss and the likes! Very high in salts and fats and oils that aren't healthy for us let alone the fishies!
Good luck! I hope you find the above useful.
~~Colesea