Tetras: reddening at base of fin

[Hoontar]

Hey all,

I have recently (4 days ago) added 16 golden tetras to my 40G tank - it was completely cycled prior to this using the fishless cycle method. After the cycle I did an 80% water change, treated the tap water etc. Since adding the fish ammonia+nitrite levels have remained at 0ppm, in a cycled tank stocked this lightly I doubt this is my problem. Anyhow, a couple of the tetras are showing reddening at the base of their fins, I was under the impression that this was a result of ammonia poisoning, but I've ruled that out... Theories and hopefully solutions anyone?

I should mention that behaviourally they seem fine, eating and swimming around comfortably. Should I water change and wait it out? Perhaps they need medicating? Maybe I didn't catch all of the chlorine and chloramine during my big water change...

 

[Sharkee]

First thing that I wouldn't do to a new tank is add 16 fishes at once. You should only add 1-3 at a time. Let your tank adjust then add another 1-3 after a week or two. Stocking is done over a period of time and not just done at once. Keep an eye on your parameter. This may cause your tank to have another cycle and that won't do your fishes any good.

 

[littletankbigworld]

How long did it take for your fishless cycle? Some people don't wait long enough...

 

[misterking]

How long did it take for your fishless cycle? Some people don't wait long enough...

They already mentioned their readings for ammonia and nitrite and as they're both 0, we can rule poisoning out, even if cycling wasn't done long enough.

Red fins in gold tetras can be a sign of male breeding coloration. Has it happened to all the fish or just a few? Most fish colour up after they've settled as it is.

 

[Hoontar]

Not all of the tetras have reddening - two days after my initial post and the ammonia & nitrite levels are still 0, I did a 15% water change 2 days ago just in case something was stressing the fish... I've also been feeding them only once every other day to reduce waste temporarily. Admittedly it does look more like ammonia burns than a breeding coloration despite my levels being at zero... Should I just keep it up with the frequent water changes and cross my fingers? The fish are still behaviourally normal.

(UPDATE) I just found this in an article published by the South Western Michigan Aquarium Society It is thought that the gold coloration results from specific conditions in their natural habitat, since aquarium raised fry do not have this coloration. Gold Tetras have a black spot at the base of the tail with red coloration above and below it.

Perhaps I am simply so unfamiliar with the breed that I am mistaking the red coloration as a sign of stress when it is in fact merely natural? After reading several similar descriptions (red fins, especially on males) I'm increasingly thinking I was worried about nothing. Time will tell.