I would suggest upgrading to a 10 gallon tank.
The answer depends on the number of guppies. A few guppies can live in a 2.5 gallon tank or larger, temperature between 72 and 80 degrees Fahrenheit. Many people raise fancy guppies in 5.5 and 10 gallon tanks.
You do not say if the guppies are common guppies or fancy, also how many male and female guppies you have, yes as far as the snails and guppies go, one point to remember is the tank water should be above 72 degrees and some live floating plants for the guppies too hide in.
no
4,000
If you have six pregnant guppies then yes, they will give birth in your five gallon tank. That tank is not big enough for all of them to live in and the guppies will keep having babies. You will have to give them away, sell them back to the fish store, or get a much bigger tank if you plan to keep them.
Its not recommended to do that, but guppies are very hardy fish. So if you were to make sure not to over feed, and to clean the tank frequently, then yes you could keep 6 guppies in a 3 gallon tank.
No
yes they can, depending on how many guppies you plan on getting.
Bristlenose catfish (normal or albino), mollies, swordtails, black widows, some tetra species and sometimes bumblebee gobbies. There are many fish compatible with guppies.
You can keep endlers guppies in a 1.5 gallon, about 2, if you maintain it (take some water out, take uneaten food out, ect.). you should keep the tank planted well because they enjoy it. You can buy endlers at petsmart. :)
yes
Guppies are very adaptable and small in size so a very large tank is not required for them to be happy in. A 20 gallon tank would be enough to keep five guppies in.