[akane]

Your other guppies might eat the fry and they might not. I have a pair that is now about 4 dozen in a 10g lol I need to ditch my "feeders" in my 30g with crayfish and just put the "fancy" guppies in there and let them weed a few out. They tend to get the big pregnant ones that can't move fast so I have to have a good starting group because I'll lose the most major breeders periodically. Problem is most slow fish that will eat guppy fry have the same risk as bettas of being aggressive and nipping the adults or having fins the adults nip and most of the fast fish evolved to live in groups so they are unhappy with less than about 5 and that doesn't fit in a 10. There's things with a lower risk you could try like a dwarf gourami. Related to bettas but less aggressive and short finned. There are a few really small cichlids if you can find a pair. You'll risk wiping the guppies out too efficiently then but they'll be interesting to watch and a pair might give you cichlid fry. Most don't stay small enough to mix with other fish in a 10 though so it would take a bit of a search. A 10g overall is best as a species tank and most people who get into fish don't just have one tank so they throw them in somewhere else to be eaten or they don't stop at a small tank if they only have 1 so they can fit a school of something. I've also got a sunfish tank that will decimate even adults. Overall fish aren't a good diet for fish though. Aside from the really big predators that concentrate on what would be a more moderate sized aquarium fish it's best to give a variety with insect or invert meat in a balanced food or as a mix so you can only feed so many guppies. Even the slightly bigger fish eat more insects than most any other food source.