What fish can you put in an unheated tank?

It's important to note that "unheated" doesn't mean "no temperature control" - it just means you don't use a heater. The temperature will be dictated by your ambient room temperature.

Here are some coldwater fish that can thrive in unheated tanks, assuming your room temperature stays between 60-70 degrees Fahrenheit (15-21 degrees Celsius):

Common Coldwater Fish:

* Goldfish: These are a classic and hardy choice, but they need a large tank to accommodate their size.

* Comet Goldfish: A long-bodied variety of goldfish that does well in colder water.

* Shubunkin Goldfish: A colorful variety with calico markings.

* Fantail Goldfish: A common type with flowing fins.

* Common Carp: Hardy fish that can tolerate a wide range of temperatures.

* Koi: Ornamental carp that can grow very large. They are best kept in a pond, but smaller koi can be kept in larger tanks.

* White Cloud Mountain Minnows: Tiny, peaceful fish that are ideal for beginners.

* Rosy Red Minnows: A colorful, active species.

* Zebra Danios: These hardy, active fish are often kept in tropical tanks, but they can survive in cooler water.

Other Options:

* Rainbow Trout: Beautiful fish that prefer cooler water, but they can be challenging to keep in captivity.

* Brook Trout: Similar to rainbow trout, these fish are best for experienced fishkeepers.

* Sticklebacks: Tiny, spiny fish that are interesting to watch.

Things to Consider:

* Tank Size: Coldwater fish still need adequate space to swim.

* Water Quality: Regular water changes are essential to maintain good water quality.

* Diet: Coldwater fish have different dietary needs than tropical fish.

* Compatibility: Make sure your chosen fish are compatible with each other.

Important Note: It's crucial to research the specific needs of any fish you're considering. Even within coldwater species, some have a more limited temperature range than others. Always prioritize the welfare of your fish!