I was wondering if 20 fish in a 4.5 gallon tank was too many.
i have 3 female guppies (approx 4 cm)
3 male guppies (approx 4 cm)
3 red platties (approx 3 cm)
1 speckly platty (approx 3 cm)
5 zebra danios ( approx 2 cm)
5 bristlenose catfish (approx 4 cm)
i do water changes twice a week and clean the filter once a week(it needs it this often). i also top up the water a little every one to two days.
i have only had one fish die (female guppy) and this was when i hadn't changed the water or cleaned the filter for 2.5 weeks