Fluval E 100 Watt Electronic Heater

Why it's worth it

The Fluval E 100 puts the real water temperature on a screen you can read from across the room, and a colored ring flags the tank when it runs too warm or too cool. It's the rare heater that tells you something's wrong before your fish do.

The Fluval E takes the guesswork out of a dial. It reads the water with two sensors and shows the number on an LCD you can see from the couch. You set your target in half-degree steps, so you're not nudging a plastic knob and hoping for the best. If you've ever squinted at a dial and wondered whether the tank was really sitting at 78, that alone is worth the swap.

The colored ring around the top is the part owners end up liking most. It glows one color when the water sits where you set it, and changes when the tank runs hot or cold. You'll catch it while you're walking past with your coffee. That's much earlier than you'd notice a fish acting off, and early is the whole game with a heater problem.

From our review of 7 aquarium heaters

What we like

• +The Fluval E takes the guesswork out of a dial
• +The colored ring around the top is the part owners end up liking most
• +It isn't the most accurate heater here
• +The built-in fish guard matters if you keep bottom dwellers

What to know

• –It's a big piece of hardware
• –More electronics means more that can quit