I hv a 4 gallloon tank with 14 guppies(7m,7f), 3redplaty,4blackmolly.

I think I am way over the limit...the tank has got a filter and airpump...i change water every week...i feed them hikari fancy guppy,micro pellets,microwafers and flakes...

D female guppy was so pregnant the stomach look so full...when i came back after dinner 2hours later, it just died...can this be coz of stress? i have got stones in the tank...(stones only cover 1/4 of the tank,the rest got no stones) for the fry to hide...but the female guppy jz died suddenly..ouch...

and some males just suffer from the tail rotting...then cant swim and died...quite a lot died during that period...

what shall i do? and how many fish can i keep in that tank?