Hey guess im new to the forum so thought i would post some of my comments and questions i have about my own fish tank. i want some advice on a few things about my 35 litre community tank which i have had nearly a year now. The tank contains 5 X Zebra danio and 1X Hillstream loach. I know that with this amount of fish in my tank i have not over stocked as my tank is around 7 gallons and all my fish are under a inch in size however i would like to know if Guppies are good community fish as i would like to add only one or 2 more fish to my tank to add more colour. As guppies are small fish i know that i should still be okay for the size of my tank but what i would like to know is that can guppies live with zebra dainos and hillstream loaches? also it is advisable to add more fish to an already established community tank as this tank has been running fine with these fish in for months? and if guppies are okay to add then what sex and how many of them should i add? Another question is that is it possible to have a fish tank that very rarely needs a tank change as i have had my tank over a year and has only been cleaned out 3 or 4 times at most as it never becomes murky or dirty and the fish seem very healthy? this may be due to the amount of food i give the fish as i still have the same small tub of fish food from when i first bought the tank!!!!!? i only feed the fish once every 3 or 4 days and even then i only give them a little amount of food i feel i have accendently created the perefect balance in my fish tank lol. they seem to have enough food in the tank over 3 or 4 days despite how little amount i give them and i know that this is perfect due to the fact that fish food left uneaten at the bottom of the tank can couse major problems. Thank you for anyone who cares to read this and answer any of the questions i have