Samantha's New Fish

Every time we move Jim and I get Samantha something special, well at least when she was old enough to understand. When we moved to Texas she got a nice playground that took up our WHOLE back yard (yards are VERY small there), when we moved to Indiana we got her camping goodies (yes, she asked for this and no, we have never used it) and when we moved to Canada Samantha asked for a fish tank with fish. So, three months later we headed to Walmart to picked up the fish tank, heater (she got tropical fish), filter, food, Safe Water (to make water safe for fish), two fake plants (one that glows), sunkin' ship, castle and 15 fish. Yes, 15 fish, she kept asking Jim can I get two of these fish, how about two of these and Jim said get whatever you want. We got home and Jim opened the fish tank and it was broken so off he went back to Walmart to switch the tank, couldn't wait another day or the 15 fish would not make it. When he got back Samantha was so excited about getting it set up. It didn't take that long and the fish were in the tank. I have told Samantha that I will NOT be responsible for the fish. Samantha has to feed them twice a day and clean the tank and rocks every other month. I am wondering how long the fish will live.