Don't euthanize that tetra! It might not have NTD!

[brry]

A bottle of clove oil in hand and tears in my eyes, I was minutes away from administering the lethal dose.

Then after more internet digging I figured out - there was nothing wrong with my fish. Nope. Nothing at all.

Problem is - when you first do a google search for "pale tetra" Or "tetra losing color" the first thing that's going to pop up is Neon Tetra Disease, which they may not have at all.

When your tetras turns pale, almost clear, in fact, turn on the overhead light and see if their color doesn't come back in an hour or so. If they are still swimming and eating normally, your fish do NOT have neon tetra disease.

I repeat - your fish do not have neon tetra disease.

They have a physiological response to darkness that causes them to lose colors when it gets dark. It is likely an adaptation that makes them less visible to predators at night when they are less active and "sleeping".

They could be pale because your aquarium is in a dim spot in your house where there is not much light exposure. (Mine is.) Or they might turn pale because you turned off the over head light, so their little fishy minds think it is "night time".

A startled fish owner could easily assume, like I did, "Oh my God, Neon Tetra Disease!" Especially if you have never seen your fish perform this particular trick before.

I thought my whole tank was infected with this totally incurable disease and I was going to have to put down all my fish, break down my entire aquarium and start over from scratch.

So I am leaving this here for the next person who thinks they are in Neon Tetra Disease h*ll.

[mfdrookie516]

All fish turn pale when the lights are off. NTD is not a common disease. I don't know that there's been a proven case of it here in the almost 3 years I've been here. It's really easy to blame something else as NTD and be done with it... it used to be dwarf gourami disease, now it's NTD

[brry]

If the other fish got any lighter at all it was so slight as to be unnoticeable.

Unlike tetras, who can turn so clear you can see their insides.

[LyndaB]

Originally Posted by mfdrookie516

All fish turn pale when the lights are off.

+ 1...... until new fishkeepers hear this, it's easy to get psyched out about it.

I've had fish also pale out during water changes, after decor was moved, during introduction of a new species to the tank, etc. There are many scenarios where they will do this.

[brry]

All fish turn pale when the lights are off.

Actually, they don't.

They are in there with other fish, whom I am looking at right now. If they have got any lighter at all it is so slight as to be totally unnoticeable.

Over the years I have had gourami, loaches, betta, goldfish, guppies - and never in my life witnessed any of them change color.

Now if they had, I would hardly have been surprised or thought anything was amiss with the tetra. I would have taken it for normal.

Tetra seem to have a unique talent in the color change area.

I am not the only one who has been startled by the effect, there are quotes like this all over the web:

I just bought a school of neon tetra. When I turned off the over-head lamp they got pale but as soon as i turned it back on they went back to there normal color.

I'm afraid the "all fish change color" quote will confuse someone, and when they notice their tetra have turned pale but the other fish have not, think something is wrong.

They could pull their tetra out of the tank, stressing them, expose them to unnecessary medications, or because NTD is incurable, euthanize them needlessly.

[LyndaB]

Maybe it should read "all species might turn pale"..... I've observed it in the vast majority of my species. Some actually turn darker during the night, like my blood parrots.

I think the reason you see it written all over is simply because that fishkeeper has never come across it before.