I currently have a freshwater tank which holds three Guppies. I was thinking, would it be at all possible to slowly converts it to a saltwater tank? I would slowly add the salt over several months, as to not kill the Guppies. Then when the tank had the correct salinity of a saltwater tank, I will remove the current sand and then add live sand and live rock. Is this even feasible? Would I need to buy a new filter and cycle it for saltwater or would my filter that is currently in the tank that was cycled in pure freshwater suffice? The tank is around 8 gallons. Here is the tank inhabitants I would like, obviously I can't have them all in my small tank. How many of them can I keep? How do I care for them?The inhabitants are in order with the inhibtants I want the most at the top of the list.
3x Guppies (Poecilia Reticulata)
2x Neon Blue Gobies (Elacatinus Oceanops)
1x Yellowhead Jawfish (Opistognathus Aurifrons)
2x Firefish (Nemateleotris magnifica)
2x Peppermint Shrimp (Lysmata wurdemanni)
6x Various Zoanthids (Zoantharia)
1x Green Star Polyp (Briareium sp)
Thanks in advance!