One of my small tropical fish ponds is in a 70 gal trough. I bought about
8-10 containers of polished rock (sizes larger +1.5" and flat). Rocks can
be purchased at Wal-Mart, osh, similar places. They look nice on bottom with
plants like anacharis anchored in them. I siphon vac around them about once
a month. If your trough is in-ground and you use a shop vac or water hose
siphon, the rocks will tend to jam in the vac. The rocks are kept clean by
cory catfish. I have had goldfish and cory's in same trough without trouble.
Sandra

"Jan" wrote in message
...
I have installed a stock tank this year and was wondering what could be
used
on the bottom of it to hide the gray color of the tank..? I understand
rocks or pea gravel is not a good idea for goldfish...
thanks..
jan