I absolutely never write reviews for apps, but this one is so good I had to give my thanks to the creators. This game is fun, challenging, and you dont have to spend a fortune to actually play it. You pay the money to buy the app and thats it. No ads, no in-app purchases! To all the reviewers who are saying their fish get sick and die, that is because you have not really learned the game. Yes, it is challenging. Thats what makes it fun! My only minor complaint is that the graphics are poor quality. Also, it is nearly impossible to tell when some of the light colored fish have ich. I would really like it if you could purchase additional tanks. I feel like you should be able to buy as many as you want. If you have the money, why cant you buy what you want? Also, I purchased this game for my iPhone, but if I want to play it on my iPad I have to buy the iPad version