The goldfish were o.k. for a few days and then one died and
the others are now doing poorly.

Others? How many are there?

Goldfish are thick-bodied, fast-growing fish that produce a lot of waste. They
will eventually get to be quite large, so they need 20-30 gallons each. And
they should not be kept alone. Therefore, I wouldn't keep goldfish in anything
less than a 50 gallon tank, and even then, only two goldfish, no more and no
less.

I suspect your problem is that your tank is overstocked. Have you checked your
water quality? (Ammonia and nitrite?) You said "the last of your fish," as if
there was only one, or only a few. If there was only one harlequin in the
tank, and you replaced it with a bunch of goldfish...well, it would be like
cycling the tank all over again.



Leigh

http://www.fortunecity.com/lavender/halloween/881/