It shouldn't. A pH of 5.5 is much too acid to keep tropical fish. The only fish that will survive at this pH are species that are specifically adapted to very acid water, such as chocolate gouramis and some tetras. If you want to keep tropical fish, you will need to buffer the pH by adding something like oxy blocks to your water.
A low pH level means that the water is acidic. The main thing to understand is that not all water is equal. Different water bodies (rivers, lakes, etc) have different water chemistry, and therefore a different pH. So various fish species have evolved to live in water with various pH levels. There are fish that are most comfortable at around 6.4, fish that are comfortable around neutral, and fish that are fine living in water as high as pH 9. So it's really a matter of doing your research. If you have acidic water, it's a lot easier to choose fish that are already adapted to living in this sort of water (like tetras, barbs, rasboras and corydoras catfish) than to try and adjust it. A low pH level is only bad for some fish.
7.0 means your water is neutral rather than acidic or alkaline. If the pH is higher than 7.0 than your water is alkaline and a pH lower of 7.0 is acidic. The pH shouldn't be 7.0 for all fish, For Freshwater Fish the pH should remain constant and Saltwater Fish should have the correct pH there species prefer. Some fish need the water acidic(lower than 7.0) and some fish like the water alkaline(higher than 7.0). So it shouldn't really be 7.0 it should be what the species of fish prefers but it is often around 7. It doesn't matter if the fish is tropical or not, Tropical Angelfish prefer the water more alkaline and other tropical fish prefer it more acidic.
pH level of six
While the exact pH level for fish reproduction varies between species, a pH level below 6.0-6.5 reduces the ability of fish to reproduce.
Since the pH is low, the acidity would be high. The acid would kill the fish not long after it is placed in the lake.
Very low pH
If the pH level is to high or low, it can kill the animals in the river.
It is important for a fish aquarium owner to purchase a ph probe for their tank. It helps measure the pH levels in the water. Certain types of fish will only survive in water with a certain pH level and one would need to know what their tank pH level is for their fish to survive.
depends.
high acidity
7=neutral, more is basic and less is acidic Both too high and too low are bad, but it really depends on the situation.
Betta fish are not terribly sensitive to pH. A pH between 5.5 and 8.5 would probably cause no problems.
It should always be 7.0!!
Polution or just a low pH level in the rain. (low pH means stronger acid)