I have 2 in my 5 gallon with a guppy
I also threw my 2 BB gobies in there because it was a PITA to feed them in my community tank. So far no squabbles, no spikes and no issues aside not having enough pond snails. I feed them frozen blood worms with a turkey baster as well. One loves them and will come right to the tip to grab them like my gobies do and the other could care less. Hes not skinny though so I know hes eating something. I have ponds and MTS in there.
One mistake I think I made was (if you see my setup) using large rocks for the look. I find the snails stay below them in the gravel most of the time. I know they peck the newly hatched ponds and probably an MTS here or there but Ive been thinking of alternate ways to get them snails. I know the java moss attracts them out and I also threw a piece of iceberg in there which does nothing. I saw online some guy actually made a small tray on a handle he puts snails in then drops them down and his puffers were going nuts.
I do a 50% WC each week and keep my filter clean.
You wont be able to sex them until their older. Ive read they also dont even develop their sex until maturity so you can get a group and STILL not get what you are looking for. When mature the males will have a black stripe on their belly.
Theyre neat, nothing as super fantastic as I actually anticipated to be honest.
Im hoping they get a bit bigger as they are so tiny they can barely be found half the time.
Honestly in a 10 I think you could do more than 2 or 3 if you make sure you dont overfeed and do a good clean every week. Also throw some shrimp in there. I have a ghost shrimp (sorry forgot to mention that earlier). He is not bothered at all and eats all the leftover food they discard.
watching the guppy swim in there youd think this was my tank lol