I'll lay it out straight, with the facts. I promise I'm not trying to be degrading in any way, but giving you the facts you need to know. One of the types of corals I specialize in are predatory corals/filter feeding corals and invertebrates.
That is In the Genus Dendronephthya. In my (and most other experienced and knowledgeable keepers) opinion, that is the most demanding species of coral you can try to keep in captivity. It's entirely Azooxanthellate and does not get any energy from light, all of it comes from what it catches. And it's very picky about what it eats.
In my personal predatory coral system I've kept and grown my 2 colonies for about 6 months now, in a 24 gallon specialized system that has the bioload of a 2-300 gallon system. This system houses Gorgonians, flame scallops, spiny oysters, Dendronephthya and Siphonogorgia. Mine is fed 100ml of particulate food slurry from an automatic doser every hour on the hour in order to maintain the food densities it needs to feed. If you aren't feeding it the correct foods constantly it's going to starve within a few months.
Now for the correct foods. They feed on food particles that usually range in the 1-20 micron range, they can even feed on bacteria if that gives you an idea of how small of particles it can catch. The foods you've listed are extremely large compared to what it needs to be fed, and it can't physically eat them. Shellfish diet by reed mariculture has several types of green phytoplankton as well as two sizes of Diatoms that have shown the best feeding response and growth with the ones I have personally. Diatoms also have been involved in other success stories with this Genus. I also use a powdered bacteria (Paracoccus) and the two smallest sizes of golden pearls. Again, this is not a "feed every other day" or even a "feed every day" type of predatory coral. It needs to feed constantly, where there's a slight greenish brown tint of food in the water column at all times.
Water velocity is also crucial. They come from reef slopes or walls with upwelling current that can be as fast as 40 cm/s. They feed well in the 10-20 cm/s range which is still a lot of flow. But it's needed in order for it to inflate properly and allow the polyps adequate chance of capturing as many food particles as possible.
You need to be willing to keep up with its needs in order for it to survive for any measurable amount of time. If you'd like clarification on anything i said please ask, or send me a PM we can talk more. But don't just let it starve.
