I have done SW and FW. Goldies are different than tropicals. No heater, as they do better at temps below 75 degrees. Heater only if your temps will swing really low, then the heater can help keep it stable. Good filtration for goldies, HOB or CAnister, or a sump setup will all work. and a python for gravel vacs and water changes needed too. You probably have the thermometer, glass scraper, lighting (1 wpg enough for fish display). Protein skimmers do not work on FW, or at least in any manner worth bothering with them. SW test kits kinda cross over (all but the nitrate are supposed to work), but since a FW kit is about $15 online, why bother.
So essentially, the principles are basically the same, so everything you used for SW should work. If you had a live rock sump for your SW, you would need to covert it to a bioball sump for fw. But witht he exception of live rock, protein skimmers, and other funky SW things, all hardware should work.