The vinegar eels are a good first food, but whatever you feed, try not to feed them too early. It could foul up the water too quickly if their in a smaller container. Also, if you really want to be successful, try getting 6 or 7 more and maybe then you could have 2 or 3 pairs going. You may have more success with a different pair. Not to say you can't be successful with these two, but it definitely increases your chances and will give you more practice hatching the eggs and playing with different parameters.
Not to mention, if you have multiple pairs in the same tank, they will release hormones when spawning and get the other pairs spawning too.
Joe