How big a fish can you have in 30 gallon?

The maximum size of fish you can have in a 30-gallon tank depends on several factors, including the species of fish, their adult size, and their compatibility with each other. Some smaller fish species that are suitable for a 30-gallon tank include:

* Neon tetras (Paracheirodon innesi): These small, colorful fish can grow up to 1.5 inches in length and are peaceful and easy to care for, making them a good choice for beginners.

* Cardinal tetras (Paracheirodon axelrodi): Similar to neon tetras, cardinal tetras can grow up to 2 inches in length and are known for their vibrant red coloration.

* Rummy nose tetras (Hemigrammus bleheri): These fish have a distinctive red nose and can grow up to 2 inches in length. They are peaceful and active, making them a good choice for a community tank.

* Zebra danios (Danio rerio): These hardy and active fish can grow up to 2 inches in length and are known for their black and white stripes.

* Guppies (Poecilia reticulata): Guppies are livebearers and can grow up to 2 inches in length. They are available in a wide variety of colors and patterns and are relatively easy to care for.

* Platies (Xiphophorus maculatus): These livebearers can grow up to 3 inches in length and come in various colors. They are peaceful and hardy, making them a good choice for beginners.

* Swordtails (Xiphophorus hellerii): Swordtails are also livebearers and can grow up to 6 inches in length. They are known for the sword-like extension on the lower part of their tail.

Remember, when selecting fish for your tank, consider their compatibility, water requirements, and activity level to ensure a healthy and harmonious aquarium environment. It's always best to research and choose the species of fish most suited for your tank size and setup.