Stressed aquarium over night

[izzy]

Since past Sunday night I am observing strange behaviour of my freshwater tank. First the basic things to get background.

It is 55 gal tank with Penguin 330 bio-wheel filter and UGF with 2 power heads. Also has 2 heaters (set to 78F) and air pump and air-stone/stick.

It has live plants and few ornaments.

As far as fish are concerned:

8 zebra danios
8 lemon tetras
4 corys
5 sunset fire platys
5 neon tetras
1 plecko

I have tested the water and PH is 7, amonia, nitrites and nitrates are in the "safe" zone (based on the test strips I have). I even had water tested at the pet store and they came up with "water is fine" as well.

Now for the problem.

It seems my tank gets stressed over night (each night!). This manifests with pale fish, neons are practically white, plecko is pink, lemon tetras are vertical etc...

As soon as I start water change in the morning their color improves. I have done 10-50% water changes every morning this week and after I am done, they are good for the day.

Since I had to do morning changes and I was getting pressed for time in the morning I decided one night to do a preventive 10% water change the night before. It didn't help! I had to change water in the morning as well. After I finish the water change, the fish gain their color almost immediately and start swimming around "as nothing happened".

The only change just before this started is addition of 2 lemon tetras on Friday before. However I was closly monitoring the amonia and it was ok.

I am confused and don't know what to do really. I started this fish tank in april and I went a month before adding last 2 lemon tetras.

 

[Terry]

My question to you is

why are you doing so many water changes

You have filtration and heating and lighting. your aquarium is planted and you have a lovely enviroment for the fish you have got, you should be doing your water changes on a weekly bases not daily. i would like to here from you to find out why you are doing so many water changes.

 

[izzy]

Terry,

My fish were doing fine until last week. I have done weekly or biweekly water changes (25% usually) and they were doing fine. However starting last Sunday night fish are stressed. I needed to do water change to help them out (as I mentioned - neon tetras were practically white!). Now I have around 10-20% water change every morning to help them out. I can't figure out what is wrong. If I preventively change water in the evening it doesn't help, they are still stressed out in the morning.

 

[RogerMcAllen]

Correct me if I'm wrong, but don't most neons lose their colors at night? The same thing happens to many fish if you switch your lights on all of a sudden at night. A dulling of colors helps protect them at night in the wild.

 

[Guest]

Have you just tried waiting a while after turning on the lights? My fish get kind of pale in the dark, and don't ge full color till they "wake up" a while after the lights are on.

What is your lighting schedule?

 

[Terry]

I think that you should leave you fish to settle down, the constant water changes are probably stressing your fish as well. If you water perameters are fine then i think that you should just leave them alone. i think that you are worrying about nothing. As Rogermcallen said fish do change colour at night for protection against preditors.

 

[Allivymar]

Every night huh. Is it a very well planted tank? I may be way off base here (and from reading your info I think I am), but I remembered that during the night, plants give off CO2, and absorb O2. Also, higher CO2 levels can make the water more acidic. I'm guessing you don't turn the aerator off during the night (some people do; apparently the sound annoys them although I don't recommend it) and I kind of doubt high CO2 levels are the prob, but its the first thing I think of when someone mentions problems that occur overnight.

If you don't have one, grab a Ph test, and test your water in the late afternoon, and test again first thing in the morning. If theres more then a full point diff, that may be your problem.

 

[izzy]

I don't turn off the aerator. The only think that gets turned off is the lights. They go off at 11pm usually.

I doubt that pale color is all due to lights off. Reason why I think fish are stressed is that even pleco is pale and lemon tetras are "flipping" around (i.e. vertical with head down or turning around and around).

Air pump supplies air to the aerator stone as well as to the two power heads so there are 3 sources of bubbles in the tank.

I will try and measure the pH in the evening as well as first thing in the morning. I will also leave the lights (neon lights) on all night and see what happens in the morning.

 

[izzy]

I just left the lights on overnight. Fish seemed to survive it much better. They were not pale in the morning. Maybe is the light. Hope it is as simple as that.

Are there any bad consequences of leaving light in the tank on 24/7?

 

[SixFootDaisy]

Lots and lots and lots of algae!

Most of my fish sleep vertically as well. I used to think they were just insane, but now I guess it is what they have to do. My tetras [Red finned and Pristella] usually sleep this way, I haven't ever seen my Gouramis do that.

I have also observed that my fish 'freak out' if I turn the light on suddenly. What I normally do is turn the room light on for about 15 minutes before I turn the tank light on. The sun doesnt just automatically come on, right? Doing this has improved the 'start of the day' for my fishfaces.

 

[izzy]

You guys were right! Fish were pale just because it was early in the morning and lights just came up. I was worried for nothing!

Thank you for help!