What size tank for a 3-5 inch fish?

The size tank you need for a 3-5 inch fish depends on the species of fish and its adult size. For example, a small fish that may only reach 3-4 inches as adults may be perfectly happy in a 10 gallon tank. However, a more active fish that will reach or exceed 5 inches, or a fish that is territorial and will need plenty of swimming room, may need a tank of at least 30 gallons.

If you are not sure what the adult size of your fish will be, it is always best to err on the side of caution and choose a larger tank. This will help ensure your fish has plenty of space to swim, explore, and display natural behaviors.

Here are some general tank size guidelines for different types of 3-5 inch fish:

* Small, inactive fish (e.g. neon tetras, pygmy cories): 10 gallons

* Active fish that will reach 4-5 inches (e.g. mollies, platies): 20 gallons

* Territorial fish that will reach or exceed 5 inches (e.g. angelfish, gouramis): 30 gallons or larger

In addition to the fish's size and activity level, you also need to take into account the other elements you want to include in the tank. For example, if you want to add live plants, you will need to make sure the tank is large enough to accommodate the plants and still give the fish plenty of room to swim. You will also need to consider the tank's filtration system and ensure that it is adequate for the size and bioload of the tank.

If you are ever in doubt about what size tank you need for your 3-5 inch fish, it is always best to consult with a qualified aquarium expert. They can help you choose the right tank size based on your fish's needs and your own personal preferences.