No fish can purify water. Fish live in the water, must eat in the water, also want to excrete in the water, so as long as fish farming will make the water deteriorate, but the relationship between the length of time. Although some fish can clean up residual bait and algae, it is only temporary, and it is also polluted after becoming excrement. Therefore, in order to improve water quality, we should not only change water at ordinary times, but also strengthen filtration.

1. Scavenger: Scavenger is the most common tool fish. As its name suggests, it can clean up the residual bait in the water, thus alleviating the deterioration of water quality. However, it should be noted that scavengers can't clean up feces, and their own excretion is also very large, so they can't really improve the water body, but only make the fish tank look clean in a short time.

2. Golden moss mouse: Golden moss mouse is moss mouse, which is a common algae-eating fish with mild personality and can be mixed with many small fish. As a tropical fish, it has certain requirements for water temperature, which is usually controlled between 15-30 ℃. It should be noted that this kind of fish only eats algae when it is young, and will suck scales of other fish when it grows up, so it should be raised separately.

3, Elf: Elf fish is a very good algae-eating fish. It only feeds on algae. The advantage is that it cleans up quickly, and it is not spoiled by other feeds like black-line flying foxes, but the disadvantage is that once there is no algae, it will starve to death, so it needs to feed some food with algae.