Panut

I still got much to learn from you, Doctor (Michael)Angelo

Now with salt in the tank, acclimatising a new guppy into the tank must be gradual, especially if the new guppy comes from pure freshwater. Difference in salinity and sudden change of water parameters may cause the guppy to be stressed, making it vulnerable to disease, which may ultimately prove to be fatal.

I personally like to use the drip method to acclimatise all my new fishes. No casualties so far.

I believe many people keep guppies without a filtration system, or without a good filtration system.. That isn't a problem, many dedicated guppy breeders around the world have been successful with the 100% WC daily and a sponge filter only.. In my humble opinion though, with a good mechanical and bio filtration system, keeping more sensitive strains such as delta tails, RREA, solid colours would be much easier without having to worry about bad water parameters which may cause fin rot, clamp fins, etc etc. Even then, i still change 30%-50% of my water daily. So far so good, hopefully my guppies will pass away naturally due to old age