Best aquarium temperatures to keep your tank is a vastly opinionated subject. It really depends on what you’re going to put into your tank. If you are serious about your tank and the livestock you put in it, you will have to keep many different water quality parameters in line. You will need to do better than “I think I’ll put a orange fishie in there.” Way better.
This discussion primarily focuses on saltwater (marine) aquariums, however there are a few references to freshwater further in the article.
There are basically three types of marine aquariums. 1. Fish – 2. Fish/Reef – 3. Reef. Yes, there are many “types” in between these, but the lowest common denominator there are basically three. Within each of these three there are many different parameters that all need to be maintained properly in order to keep the micro-eco system in check with the type of livestock that are to live in it. What is going to live in the tank, alone determines the ideal aquarium temperature along with other perimeters. Usually these perimeters have a fairly easy to maintain range in order to keep a thriving display tank, but lack of attention can quickly turn a great looking display into a costly morgue.
The complexity of the maintenance of marine aquariums pretty much follows the numbers above. Number one is the easiest to maintain. Number two falls in the intermediate and are more complex than number one and easier than number three. By far, number three is the hardest. There are more parameters to keep track of, and the tolerances are much closer together. Plus, the livestock is more expensive. One wrong move, and the whole thing goes to poop.
I personally feel my pleasure point is between numbers one and two, as I feel a reef tank takes more time than I seem to be willing to give. Plus, I’m operating a 1980’s “old-skool” type “wet/dry” filter, and I’m not sure that my stand would be able to properly hold the newer type filters either.
Since we are talking temperatures here, my experience is that mixed reef tanks as well as the reef-only ones generally run a bit hotter (warmer) than a mostly “fish” aquarium. They also seem to require more light as well.
Saltwater fish typically come from the tropics. They seem to like a range of around 75-80 F. The best thing to do is ask when you are looking at the fish at the Local Pet Store (LPS) what temperature the fish you are interested like. A knowledgeable person would know or be able to find out fairly easy. If not, the Internet might be the best source.
For “typical” freshwater fish, the temps most shops recommend is between 70 and 78 F. However, just like marine fish, there are several fish that require higher or lower temps depending on their natural habitat. So, don’t be afraid to ask or look around. An example of this is that Betta fish can survive in temperatures as high as 70-85 F.
Anyway,in doing some research on this topic, I found a chart on the net that seems to have temperatures along with other vital parameters. Since this info is vital to our aquarium hobby, I decided to include the whole thing right here. These guys seem to know what they are talking about, so below is the reference to their page, which has a lot of great info.
The table below summarizes ideal water conditions for selected Freshwater and Marine aquarium environments:
*Although some fish require special water conditions, the above listing is an average for most fish.
So in summary, the ideal aquarium temperatures vary depending on many different conditions.