Looking to Add New Fish to Established 20 Gal Tank with Fish

[NorthPoleFish]

I have a 20 gal tank that has been established for almost a year now. I currently have 5 fish and a couple snails living in it. I have one blue platy and then 4 of her babies that are grown living in the tank. I am looking at adding a small school of fish of either some kind of guppy, swordtails, tetras, or zebra danio. All depends on what our local PetCo has. (The only pet store that sells fish where I live). I have a 3 gal cylinder tank that has been established for over 2 years now and only has two snails that live in it. I have been reading on how to introduce new fish to an established tank that already has fish and quarantine the new fish is the best option to go. I've read that quarantining for up to 2 weeks is the best option to make sure the new fish from the store don't introduce disease/bacteria into your establish tank.

So, my question is, would my 3 gal cylinder tank work as a quarantine tank for a week or two while I monitor the new fish for any disease?

Also, I read that female betas can also be good tank mates with platys. Is that true? Would a female beta be a good community fish in a 20 gal tank with 5 platys and maybe 3 or 4 guppies or another small type of fish?

Thank you for your input.

 

[NorthPoleFish]

I'm still interested in information if my 3 gal tank will work as a quarantine tank for a week or so.

 

[Fishkeeper123]

I would just do the 3 gallon tank as a shrimp and snail tank but I said a response on your other thread. Then just risk the fish your adding, I would try and find a trusted supplier if you have one. For stocking, I would get some cories, choose whichever species are your favourite and get say 6-8. Then I would add maybe a single centrepiece fish like a Bolivian ram or honey gourami, and that would be a fully stocked tank. I would only do one livebearer in a 20 gallon because you will have a lot of fry to deal with. I’ve not kept bettas so I’ll duck the question about keeping a female betta with platies.