8

Fish swimming with their mouth constantly glued to water surface is a sign that they are gasping for breath. However, the reason for them being short for breath usually isn't the low oxygen concentration in the water itself, but toxic effect of water pollutants: ammonia (NH3), which burns fish's gills and disables them from extracting oxygen from the water; ...


4

First we need to clarify, what is exactly in the bottled water: To make it sparkle, the companies add CO2 gas. (In some dwells this gas was taken by the water, when dropping through the different layers of soil/stone). As long as the water is under pressure, this gas is dissolved in the water. Only around 0.2%[1][3] of this dissolved CO2 will react with the ...


4

The existing answer gives a good course of action and one of the comments suggesting the source of the fish (i.e. the local fish store) might be a good one to follow up. Some fish stores even offer a guarantee with their fish (if it dies within a week, they'll replace provided your water quality is fine). Consider changing your fish store for bettas if ...


4

High concentration of nitrite ions (1 mg/L of NO2-) is the most concerning thing in the list of your water parameters; it is many times above the toxicity threshold, because nitrites may start to become toxic at levels as low as 0.1 mg/L. Mechanism of toxicity is that NO2- ions get absorbed into the bloodstream through gills and oxidize hemoglobin in fish's ...


2

I know you fish is an indoor fish, but all fish have similar needs. Our outdoor Koi have many of the same needs. I agree with Omar and Lila. Our pond was built incorrectly and we had to get extra and better equipment to filter the water and add new water from waterfalls as the fish grew from 9" to 20". Test the water weekly and assure that your ...


2

First thing you should do is isolate your fish on a medic tank just in case it does have an infectious disease it could transmit, but also for you to be able to give them some treatment without affecting the rest of the population in your tank. Secondly, observe very well. Take pictures and look for anything different than usual. White dots like sugar, ...


2

Green cloudy water is a manifestation of an algae bloom. Algae aren't always that prominently visible, but they are always present in a living aquarium. Aquarium of your friend is having recurring algae blooms because the aquarium is trying to save itself from "crashing" - in other words, from poisoning its inhabitants with excessive concentration ...


2

Since the water quality is OK (according to your statement), then the only thing remaining is that there is an infection in the tank, affecting only the betta. In this case, I would suggest to find a specialist (veterinarian?) in your area, to help you with identifying the disease and find a treatment. An alternative would be to try aquarium-compatible ...


2

Too long for a comment but not really a proper answer, so some advice. I’ve heard of "ammonia spikes" which seems to tally with your story. I’ve had them myself: beautiful fantail, white tail, red lines appeared one morning but all readings were in the safe limits. No other fish affected. The blood streaks didn’t really disappear, either, although ...


2

Assuming that we have pure, distilled water at 25 °C: its KH is 0 because it has nothing dissolved in it (more specifically, no carbonate nor bicarbonate ions); its initial pH is 7 (which is neutral pH at at 25 °C). Having said that, we must consider that water - unless it is stored in a sealed and airtight container, which aquarium certainly isn't - ...


2

Looks good. Apparently, you have some substrate for the plants; this has provided some buffering. However, I would check the pH to be sure. I accidentally killed fish once when I put many fish in a clean plastic bucket of rainwater, with no buffering. It became too acidic in a few hours from fish respiration. A possible problem is heat from the Sun, the ...


2

If your water has the buffering capacity, and you aren't running the tank at 100 degrees F (37 °C), because water basically can't hold oxygen above the mid-90's °F (above 35 °C) or so, the effect of CO2 is negligible. CO2 does not displace oxygen in the water. With regard to the link, fish that live in the ocean live in an incomparably more stable ...


1

You have missed an important point, alkalinity = buffering. If you have low alkalinity water you will kill the fish. I killed about 25 swordtails once, didn't even add CO2. In rainwater, the fish themselves added enough CO2 to make it very acidic. (I was not thinking when I put them in there, it was only for several hours). I think the 400 ppm in the ...


1

What is you tapwater pH, and carbonate hardness (KH)? Without knowing this it can be hard to give advice. If your tapwater pH is high every water change will pull the tank value upwards. Adding to the answer on naturally pH-reducing elements, I can also add Alder cones, which can lower the pH and will also stain the water. I recently did a test where 8 alder ...


1

You need to find a way to get the surface water moving. You can use an aquarium airpump and an airstone or simply use a fan to blow air over the surface of the water. If you can limit the number of animals in your tank you will not need a dedicated filter in your tank; the surfaces on the plants and your tank will provide the bacteria a place to live and as ...


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