It depends on what species of octo you have, any idea? If it is a small egg species, the young are planktonic and are extremely hard to raise. If it is a large egg species, The young could be fed on amphipods and baby clams. Both of which are available from www.octopets.com.
That will all the help I can give you for now... 8)
They are 5 - 10mm long and about 30-50 of them
My tank is 55 gals. the species I do not know,this is my 2nd one ,I have had this one for approx. 2 months. I purchased it at a local pet store in Connecticut. I am new to this so my filter system is a basic one just a hanging filter which does 100 gph,bubble wands a sand base with live rocks small starfish and some soft corals.