How long have you kept fish?

For a 10-gallon tank. Choose your tank's size and the numbers follow it.

No plants

The clean look. Plastic plants count as none.

Lightly planted

A touch of green, about 1–2 plants.

Moderately planted

A proper green backdrop, about 3–4 plants across the back and the middle.

Heavily planted

A jungle. More than 4 plants, from a carpet in front to tall ones at the back.

Most filter boxes say which tank sizes they are made for, such as “20 to 30 gallons”.

Little or none

Running light, with no filter or one made for a smaller tank.

Standard filter (the default if left blank)

The usual, one filter whose box includes your tank’s size.

Oversized or sump

Going big, with a filter made for a bigger tank, two filters, or a sump.

How often some of the tank’s water is swapped for fresh, treated water.

Monthly or less

For the laid-back keeper.

Weekly (the default if left blank)

The classic routine, and the one most keepers settle into.

Twice a week or more

For the full-time fish keeper.