2, guppy: guppy is small in size, and has little demand for oxygen. It can survive without oxygen, but it should be noted that the feeding density is high, or it is necessary to ensure adequate oxygen supply.
3. Betta: Betta is a gill fan fish, which can obtain oxygen on the water surface and survive in an environment with low dissolved oxygen; China betta and Thailand betta have good tolerance to hypoxia.
4, vest fish: vest fish also has a low demand for oxygen, which can adapt to the hypoxic environment.
5. lamprey: lamprey refers to the fish of lamprey family. This small ornamental fish has bright colors, low demand for oxygen, and is easy to raise.
6. Scavenger: Scavenger is an omnivorous fish with low demand for oxygen, which can clean up the residual bait and dirt in the aquarium and help maintain the water quality.
7. Marley fish: Marley fish is a small ornamental fish, which is resistant to low dissolved oxygen, so it can survive without oxygen.