is he crashing into things head on , or running his side down things ?
can you get a close up picture of him ( i know not easy as they seldom stay still lol)
is the tank fully cycled ? and have you checked amonia and nitrite ?
you really should of put the graval in first before the fish ,but hey you have done it now so just take it easy when you add it and make sure it is washed very well , you may very well get a spike after adding the gravel.
also i dont want to point out the obvious but , you do realise the tank will probably only last around 6-8 months before upgrade reqd ? ,
dont worry too much about the not eating yet , they often take a while to restart eating after being added
cheers col