[NoahLikesFish]

Whaddaya mean, too hot? — Seriously Fish in this article it talks about keeping tropical fish at cold temps

 

[ichthyogeek]

Hmm....idk. I think it greatly depends on what you're keeping and why you're keeping it. If you're just keeping a community tank, then it could work. But if you're specializing, then you're most likely going to figure out temperature for the fish you're specializing into.

That being said, some fish (mollies and guppies in addition to discus to name a few) tend to be farmed at ridiculously high temperatures to bump growth rates. So keeping those fish at room temperature might be detrimental as the fish are not used to the drop in temperature, and may not properly acclimate to that temperature.

 

[ElleDee]

I think there are more people who run their tanks unheated than you think. I decided not to when it became clear that it's impossible to buy a reliable heater new and I didn't want to run a controller on my small tanks. Temps stay in the lower 70s, which is definitely on the cooler end for chili and espei rasbora, but I've seen no evidence at all they are stressed. When I upgrade to a tank with a sump I'll do two undersized heaters on a controller, but even then I'll only heat it a couple of degrees higher than ambient, not into the upper 70s because I don't see the benefit.

Obviously some fish really need warmer temps - I would never recommend someone try this with a ram or even a betta, but I agree lots of our community fish would do fine.

 

[minorhero]

The hobby is filled with tropical and subtropical species. The latter do not need a heater. The former do need a heater. There are a few temperate species in the hobby but not many, those not only don't need a heater, they might need a chiller, especially if planning to breed.

Some species can live for a time without a heater and the only sign they are stressed will be an increased likelihood of dying to illness. Measuring temps in the wild is the only way to get a good idea of what temps should be in the aquarium but this data is very hard to come by, even harder to get a good longitudinal record.

So what are we to do about it? Well generally I like to err on the cooler side of accepted temperature ranges, but I still use a heater when its a fish with a long history of being a 'tropical' fish.

 

[NoahLikesFish]

Hmm....idk. I think it greatly depends on what you're keeping and why you're keeping it. If you're just keeping a community tank, then it could work. But if you're specializing, then you're most likely going to figure out temperature for the fish you're specializing into.

That being said, some fish (mollies and guppies in addition to discus to name a few) tend to be farmed at ridiculously high temperatures to bump growth rates. So keeping those fish at room temperature might be detrimental as the fish are not used to the drop in temperature, and may not properly acclimate to that temperature.

I agree they feed the, fish foods that they can’t digest in colder water discus collected From open water need warm water though but like with psudomugil they ususally live in shaded areas with colder water, I might unplug my heater as an experiment. It even sounds like it will help fight diseases

 

[ZChalk]

I am currently running my tank at room temperature (min 22.5C) without a heater and in the past growing up as kid, I never used heaters for my tanks. The only time when I actively used heaters was when I had a marine setup. With that said, the house temperature was probably in the 20-25C at all times.

That said, there is nothing wrong with pegging the tank at a certain temperature for consistency. However, fish are more robust than you think and certainly in the wild, rainfall, seasonal changes, night, shallowness / depth of where the fish swims will cause the water temperature to change. As long as there isn't wild swings and the room stays above 21 (70F) anecdotal opinion you should have no issues maintaining the majority of tropical freshwater fish. Of course, you'd probably want to mirror the temperature of their habitat for some of the less hardy fish or if you are interested in breeding... but I think most people can get away without a heater.

The other thing to point out is that pumps and lighting also contribute to heating the tank which also further negates the use of a heater.

 

[NoahLikesFish]

I agree usually in our planted tanks and things the ph will swing by over 1 point which is very intense and it does the same, even moreso in the wild, I wouldn’t be seriously concerned about ph kh dgh unless it was a fish like a wild low ph low tds collection point apistogramma or betta. I’m still considering taking out my heater, would it be too sudden to remove it or would it slowly go down? The main reason I wanna remove it is because of the cable lol