I have a sponge on my uptake tube.. to keep the fry from being sucked up.. but yeah.. guppies need heat.. and a cycled tank like any other fish.. pimafix + salt prolly not a good idea.. melafix alone should be good to treat any bacterial infections. i keep some floating plants in the tank, and a BN pleco since it gets alot of direct sunlight... a tank is a tank.. feeders or otherwise it needs to be balanced.. once you get a colony settled they are pretty resiliant fish but i did have a few deaths with my initial batch.