Stargurl,
Thanks for the reply. Here's more info. I have several tanks, a 55 and a 20 plus several small (1-2 gallon) Betta tanks. Just moved the fish from the 55 were at a friends house in the 20.
Set up the 55 with new gravle and added a under gravle filter to the outside filter. The fish, a red-tail shark, a Kuli and 2 Blind Cave fish are fine but 3 times I added Goldfish and they all died. Goldfish in the 20 do fine. I finally added fish to the 55, yesterday, mostly Tetras and Barbs and so far they seem fine.
As I said it's about 75 miles to the nearest pet/fish store so it will be Thursday before I get there. Plan to take a water sample from both tanks to be tested and will buy a good test kid,
Linda