[wetworks]

I have a peculiar question. I have noticed that my Rummynose Tetras appear to change color- they get pale when the lights are off! In the daytime, all of the small school of ten that I have show bright red noses and vivid markings on their tails. However, if the light has been off for more than about an hour, I have found that they show no red at all, and the tail markings are very indistinct. Has anyone else ever noticed this? Does anyone know what may cause this? Thanks!

 

[zachary908]

Most fish go pale at night. I call it sleep mode :hihi: Not exactly sure why they do it though.

 

[wetworks]

Most fish go pale at night. I call it sleep mode :hihi: Not exactly sure why they do it though.

I have only noticed it with these fish in particular, but it may be because the change is so drastic. They look like totally different fish!

 

[VeeSe]

It's just because the lights are off. I wouldn't worry if their coloration is really good during lights on.

 

[wetworks]

It's just because the lights are off. I wouldn't worry if their coloration is really good during lights on.

I am more curious about why it happens than anything. What is it that triggers the change in color and what purpose does this ability serve? It just seems peculiar to me.

 

[kamikazi]

rummy nose tetras are excellent fish to keep an eye on because they will usually give you the first warning sign that tank parameters are off. When stressed their noses will go pale.

In this case it sounds like its normal for when lights go out.

I do have one question though, do you inject CO2, pressurized or DIY?

 

[JasonG75]

Most fish go pale at night. I call it sleep mode :hihi: Not exactly sure why they do it though.

They do it to HIDE from preditors while sleeping, Cardinals do it as well.

Just remember there are TWO types of Rummies.

The Rummy-Nose Tetra gets its name from the red color of their snouts. This red stain only comes to full color when the fish is in top shape. Actually, there are 3 very similar species, the "True Rummy-Nose" from Belém (Hemigrammus rhodostomus) and two "False Rummy-Nose" from Manaus (Hemigrammus bleheri e Petitella georgiae). The subtle differences are in the size and shape of the red, and also the tail fin stripes. Oddly enough, the True Rummy-Nose is the least colorful of the three, but it's also the most resistant. These small tetras aren't as hardy as most others and are sometimes very shy, but if feeling healthy and secure they're a great school fish to have in a community or amazon tank.

 

[Kayakindude90]

I would bet that it isn't a direct cause of the light being turned off. The plants in your tank will stop producing oxygen when the lights are off. Which means O2 in your tank drops. And could potentially stress your fish enough to cause them to lose color.
I also agree with kamikazi... if you are injecting any co2, your pH will also go through swings depending on if the lights are off and on. which aren't dangerous by themselves but could alse lead to coloration changes due to stress.

 

[JasonG75]

Mine do the same thing, and has for years. Both my rummies and Cardinals go pale, it has nothing to do with O2 or Co2 or parameters. Its the way they HIDE themselves from preditors while sleeping.

PLANTS release oxygen at NIGHT (lights out)

 

[djdestructo]

I have had fish do the same in my tank. I think it has something to do with the light because as soon as I turn it on, their color comes right back.

 

[kamikazi]

reason I asked about the CO2 injection was if the CO2 is being injected at night when the lights are off it could cause unsafe build up of CO2 which gas the fish.

 

[wetworks]

I have not gotten my CO2 system up and running just yet (I have not found a diffuser I like) but once I do it will be controlled by an Aqua Medic pH computer so hopefully I do not have a problem there.

 

[wetworks]

They do it to HIDE from preditors while sleeping, Cardinals do it as well.

Just remember there are TWO types of Rummies.

The Rummy-Nose Tetra gets its name from the red color of their snouts. This red stain only comes to full color when the fish is in top shape. Actually, there are 3 very similar species, the "True Rummy-Nose" from Belém (Hemigrammus rhodostomus) and two "False Rummy-Nose" from Manaus (Hemigrammus bleheri e Petitella georgiae). The subtle differences are in the size and shape of the red, and also the tail fin stripes. Oddly enough, the True Rummy-Nose is the least colorful of the three, but it's also the most resistant. These small tetras aren't as hardy as most others and are sometimes very shy, but if feeling healthy and secure they're a great school fish to have in a community or amazon tank.

This makes good sense. The ones I have are the bleheri, and during the day they are a very vivid red. I only noticed the difference because it was so drastic.

 

[JasonG75]

I have not gotten my CO2 system up and running just yet (I have not found a diffuser I like) but once I do it will be controlled by an Aqua Medic pH computer so hopefully I do not have a problem there.

HONESTLY...the pH controller is a waste of MONEY. I thought I wanted one to until several people pointed out to me the same thing. Save your money and add it to the co2 system itself.

 

[wetworks]

HONESTLY...the pH controller is a waste of MONEY. I thought I wanted one to until several people pointed out to me the same thing. Save your money and add it to the co2 system itself.

If I had to pay for it I would probably agree with you, but I was really lucky; a friend of mine gave me two Aqua Medic pH computers for free. For the price, I have to give it a shot.

 

[RainSong]

My rummies (Hemigrammus bleheri) do the same. Actually, in the mornings, I use this as an indicator of when they are ready for food. I wait until the rummies get back their color before feeding all my fish.

 

[JasonG75]

I wait until the rummies get back their color before feeding all my fish.

YEAP... I learned this by feeding one morning and NOONE was going for it. I now wait till ALL color has returned. We also evolve with our fish.

 

[wetworks]

My rummies (Hemigrammus bleheri) do the same. Actually, in the mornings, I use this as an indicator of when they are ready for food. I wait until the rummies get back their color before feeding all my fish.

I had not considered this. Thanks for pointing it out.