They can survive in a variety of different water conditions.

When water temperature rises to 86 degrees Fahrenheit, cold-water fish tend to lose their appetites. Minimize their feedings to ensure they actually eat their food rather than allow it to rot in the water. At 86 degrees, the fish should eat only twice daily, and less than normal at each feeding -- unless the fish are babies, as baby fish can tolerate higher temperatures easier than adults. Baby fish should eat small amounts frequently.

Complete cold water fish tank Image for Goldfish Startup Kit from Pets At Home

Unfortunately, along with goldfish, they are also one of the most mistreated fish around. No matter what someone tells you in a pet store, they need a heater and a filter on their aquarium. Bettas are a tropical fish, and they will suffer if their water is kept at room temperature – especially if you experience cold winters in your area. And while they can breathe from the surface, they still need regular water changes and a filter to keep the water clean.

6 low-maintenance pet fish that basically anyone can keep alive

Like any creature fish can Cold Water Pet Fish Types Image titled Take Care of Your Fish Step 1
As long as you have a “common” species from your pet smart or petco you should be completely fine. Actually these common plecs are taking over the swamps of florida water holes becuase some aquarists have been letting them go and they are now breeding and taking over in the ponds. Lots of people keep them with goldfish tanks and goldfish are considered “cold water” fish so you should be fine.

10 Best Freshwater Fish For Beginners - ClubFauna

So what are the requirements to successfully keep goldfish? I am going to discuss only the fancy varieties because they are the ones most suited for life in an aquarium. Again, keep the larger common goldfish in ponds. First of all, the fancy varieties of goldfish are much more fragile than the unaltered forms, but they can be housed in much smaller quarters. A 55 gallon aquarium can keep three fancy goldfish comfortably for their entire lifespans (which are cut to about ten years due to health problems). There are quite a few varieties to choose from, but I would stay away from the more severely deformed specimens. You must provide good filtration and aerate the water adequately. Goldfish are extremely messy, and they like to have clean water. That is not a good combination. A powerful filter and frequent water changes are a must. At least change 25% of the water weekly to keep your goldfish in top shape. Cleaning the tank is also a must as they tend to be messy eaters leaving the leftovers to rot in the tank. In addition, goldfish are a coldwater fish. They CANNOT be housed with tropical fish. They do NOT need heaters in their tank. The higher temperatures reduce the oxygen levels in the water causing stress for the goldfish. Goldfish really should be housed with only other goldfish. If you really want to have tankmates, I can suggest white cloud mountain minnows, butterfly loaches, and apple snails as a few species that may do well with goldfish. Goldfish also happily consume live plants. Only java fern, moss, and anubias species will go untouched. Their diets need to be varied. A good quality pellet food made specifically for goldfish mixed with some green vegetable occasionally is a good start. Once again, goldfish can make excellent pets if their basic requirements are met, but they really require some effort on their owner's part. Give them a try once you have the basics of fishkeeping figured out.

Recommended fishes for cool water tanks with pictures