Are heaters really necessary?

[KuhliDude]

For the time during winter I have kept all of my aquarium heaters off. And the the temperature has gone below 70 degrees, and yet my fish are happily swimming around.

So I'm questioning whether these tropical fish are really tropical.

 

[Byron]

It depends upon the species.

 

[KuhliDude]

In that tank where the temperature is 68 degrees Fahrenheit, I have a honey gourami and two kuhli loaches.

 

[Ichthys]

Yes they’re both tropical. They both have a winter minimum of about 70ish, so I wouldn’t let them go below that.

 

[KuhliDude]

Interesting

 

[PewPewChris]

It's really a difference between whether your fish are surviving or thriving and what you want to get out of the tank

 

[GaryE]

If you take the scientific name of the fish and put it into a serious site or check a researched book, you may find we overheat. For example, the honey, in the rare case it's a real one, is Trichogaster chuna, and its range is 22 to 27. Pangio semicinta, the kuhli loach? 21 to 27.
So at 70f/21c, you are just under the bottom range for the chuna, and on it for the loaches.

Problems? Maybe, if it drops lower. Studies have shown temperature affects digestion in fish, a lot. But I would argue that while both fish can handle a high summer 27, and both will face warmer for longer periods than the short cool season, heat probably harms them longterm. Ideally, you'd want to be 23, 24 for them. Moderation...

I would use a heater, but one that you can set low.

We misunderstand tropical. In heavily forested zones, sun doesn't get through the forest canopy to warm the water, which generally flows downhill from higher elevations. I have fish here that come from places where the air is at 26 year round, but the water is at 20-21.

With many fish, a book from the 80s will say 22 degrees. By the 90s, 24. 2010? It's at 24. Now, maybe 26. Why the creep up? It's a good question, but it is a pattern in the hobby.

 

[AbbeysDad]

"Are heaters really necessary?" Well, not always. As @Byron points out, it depends on the species. And I would go a step further to say that it also depends on how COLD the ambient temperature is around the aquarium. Then too, all creatures want to survive and many can tolerate colder temperatures long before they would perish.

I have a turtle pond (a 5' kiddie pool) in my unheated basement that is about 55°F in winter. I've had some swordtails survive in that water that perish more from the turtles than from the cold. I've even had some fry grow up there that were introduced acidently from skimming duckweed from other tanks.

So it depends...in most homes where we have aquariums where the average room temperature is about 72°F, we could say that most 'tropical fish' will likely do just fine. Survival becomes more difficult in the extremes.

 

[emeraldking]

For the time during winter I have kept all of my aquarium heaters off. And the the temperature has gone below 70 degrees, and yet my fish are happily swimming around.

So I'm questioning whether these tropical fish are really tropical.

It depends on the kind of fish. Not one tank of mine has got a heater in it.
But there are so many subtropical fish that are sold as being tropical fish. But there are also tropical fish that have a wide range in temperature tolerance.
I don't know what kind of fish you have at home. But a lot of freshwater aquarium fish will do well at room temperature. We do exaggerate a lot when we are dealing with tropical fish. For most people think when they're dealing with tropical fish: Oh, then we do need a heater... At least, a store will definitely sell you a heater as a desperate need for those fish...

 

[GaryE]

You were clear about the fish you have. But if it is a wide, general questio beyond your 2 speciesn, one size fits all doesn't work. Species by species, tank by tank. I choose my fish so that I can avoid having too many heaters, since I have too many tanks. The important thing is to respect the natural history of the fish, and that means looking up its needs. Don't make fish conform to your needs - adjust to them.