If you do decide to try and raise them and the dwarf puffer doesn't call them lunch, egg yolk works great in a pinch. I recently had a group of hitchhiking mystery fry pop up in my tank of no fish. They've been on egg yolk for almost a week now. Bring the egg to a boil, continue to boil it for a minute or two, crack the egg over a strainer that has a bowl underneath to catch the remnants, remove the egg white carefully, scrape out the yolk into the strainer over the bowl, add a couple ounces of water to the liquid yolk in the bowl, and then spot feed 3 times a day. The mixture supposedly lasts for up to three days, but I redo it every other day. Also, frequent water changes will have to be done.