hi gala, been following this thread , so members are just trying to let you know that anything, even something you may think is insignificant, could be very important in deciphering the problem . So we see your tank has not finished cycling, a common mistake with new fishkeepers, especially if you purchase your fish at a local pet store or chain. They won't tell you it takes a month to cycle your tank and establish good bacteria before the tank is safe for fish because most people are not willing to wait ,they just want fish and the chain stores just want to sell fish, they dont care if a tank is ready for fish , or what kind of tankmates it will have or how big the tank is in comparisson to how big the fish will get..as i said, they just want customers to walk out that door with a purchase. So , if i may, you will need to read up on the nitrification cycle, and once it is complete, never clean ANYTHING , filters, or even add new tap water before removing chlorine if you have it in your tap . Always use used tank water when rinsing filters and add Prime or another chlorine/chloramide remover to the tank before adding new water , after vacuuming ,etc. Another suggestion is to mapquest your zip code asking for nearest aquarium only stores, and use them ,rather than the chains. They are soley in the business of selling fish/fish products and will be more helpful when purchasing fish and supplies. I can't imagine a'' fish only'' store allowing a customer to purchase these guys for an uncycled tank. They will be more helpful. As mentioned, you should seriously consider purchasing an API MASTER TEST KIT, liquid drops, not the strips, as you will need to keep an eye on your water. Also, as members mentioned ,water quality is of the utmost importance when keeping fish in an aquarium. You can imagine, in the wild, the lakes, rivers , get rain, and are much larger, whereas an aquarium is a box and becomes the fishes' home and toilet . That is why members are concerned with water changes and vacuums. As for now , try to read up on the cycle so you understand what is happening in your tank , and how to deal with it. If you are not using RO water or on well water, you need to purchase Prime or other similar. We see you want your fish to live and have asked how to help, so now you are on your way with all the advice from members here... good luck and keep us informed...sorry this was so long .