J&L has frozen plankton, and TimT has pacifica plankton. I believe Tim's is a bit smaller but it's been awhile since I bought it from Jeff

Thanks Greg, I will get them some plankton.

Update: The three fish are doing well. Twoonie eats frozen like a pig, including some flake. Loonie and Quarter peck at things, but I haven't seen them eat heartily. However, all 3 fish look well and they seem to have grown a bit. The chasing has abated somewhat, as they seem to have their own "territories" now.

I haven't medicated them at all, as I was trying to get them eating. Tonight I noticed Loonie has white stringy poop trailing behind him. I know this is symptomatic of intestinal parasites. What kind of medication do you guys recommend?

Metro for bacterial, prazi for flukes. Its hard to tell which they have without an examination of the feces with a microscope, but I'd recommend starting with prazi and seeing how they look after four days. If the poop doesn'tnormalize, switch to metronidazol.

Thanks Albert.

Update: I started Prazipro a week ago, It took me two days to bring the dosage up to the recommended level. Quarter didn't make it, though; he never ate and yesterday he went to Angel heaven, where there is no shortage of live food and sponges...

Twoonie has grown quite a bit, and Loonie look OK, although he hasn't grown as much. Yesterday I noticed him scratching on the PVC pipes. Today he is also shaking in short spurts. He clearly has something that is bugging him. I thought Prazipro would take care of flukes, so it must be smething else. I can't see anything visible, but he keeps scratching the same side.

Any ideas? I don't wnat to lose these two...

It may be the fluke after all. When the fluke dies and exits the fish body, it leaves some wounds on the body. When the wounds are healing, the fish feels itchy, just like in human. If that's the case, then scratching is normal.
Another possibility is marine ich. I saw it before that fish had marine ich was scratching but the symptom (white dots) wouldn't show up a few days later. So watch your fish closely in the next few days.
On a hind-sight, I wouldn't start the the PP until all fish are eating and fat. PP can suppress appetite for some fish. Also it's very safe to dose full dosage at once.
Good luck on your remaining pair.