Aquarium heaters are essential for maintaining a stable, healthy water temperature in tropical fish tanks. At Tropical Treasures Wyo, we offer reliable, adjustable submersible heaters sized for nano tanks up to large aquariums, keeping your fish, shrimp, and plants comfortable year-round.
Choose the right wattage for your tank size and pair your heater with dependable filtration, quiet air pumps, and aquarium tools for a complete setup — ideal for planted aquariums. Fast shipping from Wyoming nationwide.
Aquarium Heater Wattage Guide
Not sure what size heater you need? Use this quick reference to match your tank volume to the right wattage. As a general rule, aim for roughly 3–5 watts per gallon, and size up if your room runs cold or you keep warm-water species like discus.
| Tank Size |
Wattage Needed |
| Under 7 gallons |
25 watts |
| 7–16 gallons |
50 watts |
| 16–26 gallons |
75 watts |
| 26–40 gallons |
100 watts |
| 40–79 gallons |
150 watts |
| 79–106 gallons |
200 watts |
| 106–159 gallons |
250 watts |
| 159–264 gallons |
300 watts |
Shop heaters by brand: Fluval, Hygger, Aquatop, and Eheim.
For tanks larger than about 75 gallons, many aquarists run two smaller heaters instead of one large unit — it spreads heat more evenly and gives you a safety margin if one ever fails.
Choosing a Submersible Heater for Your Fish Tank
A submersible heater is a popular choice for freshwater fish tanks because it warms aquarium water directly and can be positioned near a filter outlet for even heat distribution. Many adjustable models let you set a temperature appropriate for your fish. Check the specific heater's label: a fully submersible model can be installed underwater as directed, while other heaters have a maximum waterline or different positioning requirements. Never assume every heater is fully submersible.
Nano Heater Options for Small Aquariums
A compact nano heater may be suitable for a small betta, shrimp, or planted aquarium when the heater is rated for that exact tank volume and ambient room temperature. A smaller tank can change temperature quickly, so use a separate aquarium thermometer to verify the actual water temperature. Choose adjustable equipment when practical and avoid oversized heaters that could overheat a small tank if a thermostat fails.
Fish Tank Heater Placement and Safety
Place your fish tank heater where water circulates well, away from direct contact with substrate, decorations, or delicate plants as specified by the manufacturer. Maintain the required water level and follow the installation directions for vertical or horizontal mounting. Unplug the heater before water changes that expose it to air, and let it cool before removing it. Never run an aquarium heater dry.
The wattage table above is a broad starting guide, not a guarantee: room temperature, lid coverage, aquarium shape, desired temperature, and the specific manufacturer's recommendations all affect sizing. In larger aquariums, two appropriately sized heaters can distribute heat, but they do not eliminate overheating risk; an independent temperature controller and thermometer can provide additional monitoring. Check temperatures regularly, especially after installing or replacing equipment.
Frequently Asked Questions
What size heater do I need?
A good rule of thumb is 3–5 watts per gallon, so a 20-gallon tank does well with a 75–100 watt heater. Size up if your home runs cold or you keep warm-water species like discus, and consider two smaller heaters on tanks over about 75 gallons for more even heat and a safety margin.
Do I need a heater for my aquarium?
Most tropical fish, shrimp, and plants need stable temperatures in the mid-70s to low-80s °F, so a heater is recommended for nearly all indoor tropical setups. Coldwater species like goldfish are the main exception.
Where should I place my aquarium heater?
Position it near good water flow, such as beside a filter outflow, so heat distributes evenly. Keep it fully submerged per the manufacturer’s instructions.
