

Help with guppies!
Hi!
A bit of backstory. I am a betta owner. I have had bettas for years and have recently done a lot of research and learned how to properly care for them. I know in the past that I have not given the best care to my bettas, but things have changed! I have a very well planted 10 gallon tank that i just moved my little buddy into over the weekend after cycling it for a month (he was in a planted 5 gal before this). I got this fish earlier this year and he’s a male. Well today, I went to a chain fish store with my roommate so she could get some ghost shrimp for one of her tanks. I noticed some floating plants on the shrimp tank and asked the man working if they had any floating plants for sale for my betta. He said no, but offered to let me have some of his personal stash for free. I was very grateful, but he also included 3 teeny tiny guppies that he said he wouldn’t be able to put back in the tank (for some reason idk) and they were surrendered and probably won’t survive. I felt guilty and said it was fine, but now i’m a parent to 3 baby guppies. I have only cared for bettas and have failed at caring for other types of fish in the past. The man said I could put the guppies with my betta, but he has been attacking the small cup floating in the tank with the guppies. One of the plants i bought from this store also came with a dozen bladder snails that just recently surfaced and my betta is attacking them, so i have no hope for the guppies survival should they be released in his tank.
What do I do? I have a tall 10 gallon tank that is a pain and i did NOT want to set up, but also a 5 gallon long and 2 2.5 gal tanks. I have black sand, goldfish flakes, a filter, betta conditioner, shrimp conditioner, betta pellets, a heater that is usually set to 76-82. I can move plants in there if needed. Can i use any of this stuff or do i need to buy everything new? I want to do what’s best for these guppies. Please help!!