The top ten cold water fish for naked tanks: goldfish, medaka, rock crawler, koi, Chinese fighting fish, lion head, dragon eye, butterfly tail, orchid, and pearl scale goldfish.

1. Goldfish: Goldfish is a relatively common cold-water ornamental fish in life. This fish is colorful and comes in many varieties. It is suitable for group keeping. Goldfish have strong adaptability to water temperature.

2. Guanbei Medaka: Guanbei Medaka is a new species cultivated through artificial selection, hybridization and purification of wild medaka. It is a small cold-water ornamental fish. The body shape is relatively changeable, the color is high, and the ornamental value is high. It is suitable for living in temperatures of about 15°C to 30°C.

3. Rock-climbing loach: Rock-climbing loach is a small ornamental fish. This fish usually lives on rocks and is an omnivorous fish. They mainly eat algae, red worms, and special-shaped feed to survive. The temperature of the breeding water does not exceed 28 degrees.

4. Koi: Koi is a very beautiful cold water ornamental fish. This fish has bright colors and changeable patterns, and has strong ornamental value. There are many varieties of koi, which are suitable for group keeping and have strong adaptability to water. Suitable for living in water environments with low hardness, koi eat fine algae, synthetic granular bait, and higher aquatic plant fragments.

5. Chinese Betta: Chinese Betta is a common cold-water ornamental fish that likes to live in shallow puddles or on banks with dense aquatic plants. It is suitable to live in a water temperature environment of about 24°C to 27°C, and feeds on insect larvae, fish insects, and dry bait.

6. Lion head: The lion head is a very beautiful goldfish with a unique appearance and a gentle temperament. The lion head is colorful and bright, and it is a small ornamental fish with strong ornamental value.

7. Dragon eye: This kind of fish has a beautiful appearance and large eyes, which makes it popular among many people. The body is slender, the tail stalk is slender, and the tail is very beautiful.

8. Butterfly tail: Butterfly tail is also a relatively good-looking cold water ornamental fish. This fish has large eyes and a relatively developed tail, just like a butterfly, which is particularly beautiful.

9. Lanshou: Lanshou is one of the earliest cold-water ornamental fishes in the world. It is called the king of goldfish. It generally lives in Asia and has different varieties.

10. Pearl scale goldfish: Pearl scale goldfish is a small cold water ornamental fish with a relatively beautiful appearance. The body is bulging and very beautiful. This kind of fish can be kept in fish tanks and is highly ornamental. There are different varieties, such as red pearl scales, grass green pearl scales, five-flowered pearl scales, blue lion head pearl scales, etc.