Dieing Fish

[naglefisheser]

I have had my acquarium set up since january, with mainly tetras, mollys and guppys, I have all fresh plants and gravel. Its a 95l aquarium. I have tested the water and there is no nitrites nor ammonia, but ph is 8. I just keep on losing fish at the moment and dont know why. The ph thing is very weird as if you test the water straight from the tap it is about 6 but after putting it in the aquarium it goes up to 8. I do not know what it can be as we have replaced the old gravel and all the plants a re new and fresh. Help! I dont want to loose any more fish!

 

[the_lock_man]

To test pH of tapwater, you need to leave it 24 hours before testing, many water companies put CO2 in the water, and this affects its pH.

Is your gravel the crushed coral type, or do you have any alkaline rocks in the tank? That could seriously raise pH. That said, a pH of 8.0 isn't stupidly high, yes it's on the high side, but it's not dangerously so. Do you use a pH stabiliser chemical at all?

Do you lose the fish quite soon after introducing them? How do you acclimatise the fish when you buy them?

 

[fluttermoth]

Have you tried letting the tap water stand for 24 hours before you do your pH test? Lots of water companies add CO2 to the water to help prevent pipe corrosion which lowers the pH and you nedd to let that gas off first to get a 'true' reading.

However, most fish are tolerant of differing pH levels as long as they're stable, so I'd suspect something else is going on. How big is your tank, what filtration do you have, what's your maintenance regime, what fish do have exacly, and which ones are you losing?

 

[OldMan47]

I must ask how often you do water changes since water quality is often implicated in fish deaths. I would be curious about what is raising your pH. Normally water in an aquarium gradually sees lower and lower pH until you do a water change to bring it back up. The lower pH is the result of nitrate build up since part of the nitrate present is in the form of nitric acid. I tested lots of things in one of my tanks before I finally discovered that the decorative rock in the tank would raise water pH when I let a sample of it sit in a bucket of water for a few days. It was passing things like the fizz test but slowly raised the pH to extreme levels.