was probably a good move to change all the water as long as no chlorinated water got to your filter.
You really ought to consider picking up some ammonia/nitrite and nitrate test kits.
How big are the goldies now? Seleya is right, a 10g is going to be pretty small for two goldies like yours...you'll need to make sure and do at least 50% of the water once a week normally. Plus your tank is "cycling" (beginning period when a tank is not established yet) so there are bound to be high levels of ammonia and nitrites like seleya said. After your tank is finished cycling (probably at least another month or two) then you'll just have to do as many water changes as it takes to keep your nitrates relatively low.
Did the pink tail get any better with the water change? |