Fish Happiness

Keeping your Fish World fish happy can have a positive effect on how much you make as a bonus when you are ready to sell them.

Conversely unhappy fish can have a negative effect on your bonus.

Fish stay 50% happy as long as they are fed, have a clean tank, plenty of decorations and aren’t over-crowded. If your fish aren’t happy, then you could get Sick Fish and they may need to be treated with medicine.

Remember!!! Happy fish equals extra coins!!   If you want a more detailed background on happiness, that information can be found here.


Click on a single fish in your tank. You will see a fish happiness bar. If the bar is green, your fish is happy. The fuller the bar, the more happy your fish is. If the bar is red, your fish is unhappy. Try cleaning your tank or reducing the number of fish in the tank!!!

The fish in the tank below is 100%  happy, resulting in a +1050 coin bonus when I sell him. Clicking on the little question mark to the right of the happiness bar will give you suggestions on making your fish happier.


The number of decorations in the tank will will affect your fish happiness. Put at least 8 decorations in a tank if you are just starting out. The more decorations, the better. However, your fish will not be 100% using decorations alone.

If your fish are hungry, they will also be unhappy, so make sure you feed them regularly or, if you can afford one, add a feeder to the tank to keep the fish always fed.

If the tank is dirty, your fish will not be happy either. You need to clean your tanks before selling your fish, especially if you are just starting out and don’t have any decorations. Unhappy fish means the final sales price decreases.  If you are tired of cleaning your tanks, invest in an algae eater or cleaner to do it for you.

If you put more than 100 fish per tank, your fish will be over-crowded and, thus, unhappy.

Special fish like the Dolphin and Octopus will increase the happiness levels of the fish that are in the same tank with them.

Having a premium item in a tank will make the fish 100% happy no matter how many decorations are in the tank. They will also keep your fish fed and your tank clean. So, although quite expensive, a premium is a good investment.

A deluxe tank (one you paid fishbucks for) will also provide a happiness boost, in addition to an XP boost, making for happier fish. Fish will also never get sick in a deluxe tank.


The main reasons to keep your fish happy are to prevent them from getting sick and to increase your coin bonus when you sell your fish.

The happier your fish are, the more of a coin bonus you will get when you sell. The maximum bonus is 15% of the sales price. Don’t drive yourself crazy trying to reach 100% happiness in all tanks… It’s really not that important. As long as your fish are approximately 75% happy, then you should be fine.