thanks guys .
it was very lucky for me to find those gravel down by our local river. i took three pails of it. i'll make an update of it from time to time. the fish are still a bit stressed out but they'll get over it in a few days.
the tank is a 65, 48x18x18. stock are midas fries(4) , one unknown cichlid, one endli, one leopard sailfin pleco, and one gold spot pleco. i will transfer the endli and the two plecos in a bigger tank or maybe sell them in the near future. i will try to get some pics of them tonight, where there will be no sunlight coming through the tank.