What Size Heater Does a 29 Gallon Tank Need?

Q: What size heater does a 29 gallon tank need?

Aqueon lists 100 watts for aquariums of 15-40 gallons. A 29 gallon tank is inside that band. The 50 watt band ends at 20 gallons, and the 150 watt band starts at 30 gallons.

Q: Is 29 gallons in more than one Aqueon band?

No. The 50 watt and 100 watt bands overlap only from 15 to 20 gallons. The 100 watt and 150 watt bands overlap only from 30 to 40 gallons. 29 is between those overlaps, so only 100 watts applies.

Q: Which species minimums fit a 29 gallon tank?

Minimums at or under 29 gallons in this set run from about 11 US gallons (betta and guppy) through about 14, about 19, and about 21, plus a dwarf gourami minimum of 56 liters (14.80 US gallons). Angelfish at about 53, discus at 67.37 US gallons, and oscar at about 143 do not fit.

Q: Does a species profile's 50 watt note replace the 100 watt band on a 29?

No. Profile heater watts go with that species' own minimum tank. Aqueon places a 29 gallon tank in the 100 watt band for 15-40 gallons.

100 watts is the only Aqueon band that contains 29 gallons. That band is 15-40 gallons.

Full breakdown: aquarium heater wattage guide.

Quick answer: A 29 gallon tank needs a 100 watt heater on the Aqueon chart, because 100 watts covers 15-40 gallons and 29 is inside that span. It misses the 50 watt band, which ends at 20 gallons, and it misses the 150 watt band, which starts at 30. Every Seriously Fish minimum in this set at or under 29 gallons can use this tank; angelfish at about 53, discus at 67.37, and oscar at about 143 cannot.

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The figures

Figure	Value	Source
Question size	29 gallon tank	Aqueon
Band that contains 29 gallons	100 watts for 15-40 gallons	Aqueon
50 watt band	5-20 gallons; 29 is above 20	Aqueon
150 watt band	30-55 gallons; 29 is below 30	Aqueon
200 watt band	50-75 gallons; 29 is below 50	Aqueon
300 watt band	65-90 gallons; 29 is below 65	Aqueon

How to size it

A 29 gallon tank is not a printed row. Aqueon gives ranges, and 29 has to fall inside one of them.

15 ≤ 29 ≤ 40, so 100 watts includes it. 29 > 20, so 50 watts excludes it. 29 < 30, so 150 watts excludes it.

There is no second wattage to shop for the tank itself. The 50 watt and 100 watt bands do overlap, but only from 15 through 20 gallons, and 29 is past 20. The 100 watt and 150 watt bands overlap from 30 through 40, and 29 is short of 30. A heater guard is the second product, not the neighboring wattage.

Species heater watts on the linked profiles belong to each species' own minimum tank, and several of those minimums are 11, 14, 19, or 21 gallons. Those watts are not a substitute for the 100 watt band that contains a 29. Use the species pages for the fish's own heater note. Use 100 watts for this tank because that is the band 29 gallons lands in. Temperatures below are the ranges those fish are listed at, so a 29 gallon tank that holds them still has to reach that range.

The dwarf gourami minimum is published as 56 liters, not as gallons. 56 ÷ 3.785 = 14.80 US gallons, which is under 29. No temperature is listed for that profile. Angelfish at about 53 US gallons, discus at 255 liters (67.37 US gallons), and oscar at about 143 US gallons are all above 29.

Species whose published minimum fits this tank

Published minimum at or under 29 gallons. Temperature is the species range, not a heater wattage for the 29 itself.

Species	Published minimum	Temperature	Source
Betta (Betta splendens)	about 11 US gallons	72-86°F	Seriously Fish
Neon tetra (Paracheirodon innesi)	about 14 US gallons	70-77°F	Seriously Fish
Guppy (Poecilia reticulata)	about 11 US gallons	63-82°F	Seriously Fish
Zebra danio (Danio rerio)	about 21 US gallons	64-77°F	Seriously Fish
Bronze cory (Corydoras aeneus)	about 19 US gallons	70-81°F	Seriously Fish
Platy (Xiphophorus maculatus)	about 14 US gallons	68-79°F	Seriously Fish
Molly (Poecilia sphenops)	about 21 US gallons	70-82°F	Seriously Fish
Bristlenose pleco (Ancistrus sp.)	about 19 US gallons	77-86°F	Seriously Fish
German blue ram (Mikrogeophagus ramirezi)	about 14 US gallons	81-86°F	Seriously Fish
Dwarf gourami (Trichogaster lalius)	56 liters = 14.80 US gallons	Not listed	Seriously Fish
Cherry barb (Puntius titteya)	about 14 US gallons	68-81°F	Seriously Fish
Harlequin rasbora (Trigonostigma heteromorpha)	about 14 US gallons	70-82°F	Seriously Fish

Published minimums above 29 gallons. These fish do not fit the tank this heater is being sized for:

Species	Published minimum	Temperature	Source
Angelfish (Pterophyllum scalare)	about 53 US gallons	75-86°F	Seriously Fish
Discus (Symphysodon aequifasciatus)	255 liters = 67.37 US gallons	Not listed	Seriously Fish
Oscar (Astronotus ocellatus)	about 143 US gallons	68-82°F	Seriously Fish

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