FAQs on the
Related Articles: Neons, Cardinals & Their Kin;
Selection, Maintenance & Healthcare by Neale Monks,
Tetras; A School of Beauty, Part
II, by Alesia Benedict, Characid Fishes,
FAQs on: Neon Tetras 1,
FAQs on: Neon Tetras
Identification, Neon Tetras
Behavior, Neon Tetras
Compatibility, Neon Tetras
Stocking/Selection, Neon Tetras
Systems, Neon Tetras Feeding,
Neon Tetras Disease, Neon Tetras Reproduction/Breeding,
Related FAQs: Cardinal Tetras, Characid/Tetra
neon tetra, too few in too small a world - 8/17/12
I have 2 neon Tetras
<Won't be happy in groups of less than 6; these two will pine away,
ignore their food, eventually die.>
in a 5-gallon tank.
<Too small for Neons. How long has this tank been set up? How
did you cycle the filter before adding the fish? If the tank is new, and
the filter wasn't cycled (with a source of ammonia) for 4-6 weeks before
buying, adding the fish, then it's almost certain you have non-zero
ammonia, nitrite levels, and these are stressing, killing the Neons.>
The pet store recommended a tropical granule with color enhancers as the
only food. When I drop a few granules into the tank, the fish swim
all around them, but do not go after them or eat them.
<Not at all surprising.>
They then lay on the bottom of the tank.
The granules seem too big for their small mouths. Will they munch on
those granules on the bottom or do they need a floating food?
<Neons need foods that sink slowly, e.g., a good quality flake like
Would three neons in a 5-gallon tank be to many?
<6-8 Neons in 10-gallons is the MINIMUM for this species.>
Thank you for any help you can provide. B.J. Lane
<Glad to help. All you need to do is buy a new aquarium, cycle it for 6
weeks (if you don't have any mature filter media to hand to put inside
the aquarium filter), then add the Neons. Do read:
Tetra with white mouth 2/5/11
Just to update you all, sadly, my panda platy died last night from what
we are sure was fish TB (mycobacterium). Despite not eating, she lasted
a good two weeks on twice daily water changes although her eyesight
must have failed her and her tail became covered in fungus in the last
two days - very sad.
I've got two neon tetras now waiting some sort of help. They have
had this white patch on their mouths - curiously, it's been
developing really slowly over the past two months and they appear to be
normal/eat normally. I've now put them in the hospital tank with
their tank water, air and heating.
I've not added any treatment at this stage as I wanted to check
what I should use if any. I'm thinking that it is probably
Columnaris as I found a few white spots on another tetra a few weeks
back when we had a small nitrite spike for a couple of days and which I
cleared up with a broad spectrum antibiotic. However, I've
attempted to treat this tetra before and its white patch on its mouth
didn't clear up. Is it worth treating this one again with an
antibiotic or a die-based solution for the Gram-negative bacteria?
Many thanks for you excellent help as ever.
<Yes, I agree, Columnaris is probable. But with Neons, this does
seem quite a common malaise, perhaps caused by fighting or bumping into
Would treat with something like eSHa 2000 that treats Finrot,
Columnaris and fungus all at the same time, and beyond that, hope for
the best. As ever with Neons, ensure the water isn't too hard and
the temperature isn't too high -- these are surely common mistakes
that shorten their lifespans in captivity. Cheers, Neale.>
Hi Crew Again
Hope you had your morning coffee.
I am keeping individual emails per question to make things easier
I have 7 neon tetras and the one in the picture has had a white
growth on his (male I think) lip for a couple of months now. When
I first noticed it I moved him to a hospital tanks and treat with
As he has not got worse I can only assume that what ever it was
has been treated.
This morning I noticed that one of the females has developed a
white spot on her left side (see pic) I think it may be
Not sure what to treat her with - I have an array of
Either do a Salt dip.
or JBL Ektol Fluid, JBL Ektol Crystal as well as Fungol2, Punktol
I have some Interpet anti bacterial fluid as well.
<This would appear to be Mouth Fungus, which, despite its
name, is a bacterial infection, sometimes called Columnaris (the
bacteria species is called Flavobacterium columnare, or in older
books, Flexibacter columnaris, hence the name). It isn't
difficult to treat when caught early, and an anti-Finrot
medications will usually work well. Fungus proper can look
similar, but the threads are usually longer and fluffier. Some
medications will treat both; I particularly recommend eSHa 2000
because of this, and in the UK and parts of Europe this
medication is widely sold an inexpensive. Do remember to remove
carbon from the filter, if used, while medicating. Mouth Fungus
may be caused by water quality issues, or it may be a result of
fighting or some other type of physical damage to the mouth.
Review and act accordingly.
Re: Neon Tetra
Many thanks for your reply.
<Glad to help.>
Do you think the female with the white spot just under the blue
line is the same?
<Probably not. Could be Whitespot, but for now, the Columnaris
is the priority, though the standard salt/heat method against
Whitespot could be used safely and without causing stress to your
We treated the male with mouth rot about 2 months ago - the white
on his mouth is still there but he as not got any worse, should
what looks like rot have gone away by now?
<Difficult to say. Bacterial infections may come and go
depending on the strength of the immune system, which is why they
become killers in tanks with underlying problems. The bacteria
responsible are present in all tanks, all the time. For what
it's worth, I don't recommend Neons unless you happen to
have soft water and you also have the option of keeping them
relatively cool; Neons don't do well in hard water and they
don't do well kept above 25 C/77 F. Cheers,
Tetra Neons... keeping/killing 1/24/11
Hi, I just got 5 Neons about 4 days ago, and unfortunately one of them
has already died. They are in a 10 gallon tank with a pH of about 6.5
and nitrate and nitrite readings are low as well.
<Meaning what? Is this aquarium brand new? A new tank *will* kill
Neons. It needs to be cycled for 3-4 weeks at least before adding the
Neons. By cycling, we mean presenting a source of ammonia, such as
pinches of fish food every couple of days, and then doing the usual 25%
water changes every week. If the tank is new, ammonia will be high for
the first couple of weeks, nitrite high for about weeks 2 to 4, and
only after the fourth week will ammonia and nitrite both be close to
(or at) zero, and that's when nitrate starts going up. That's
also the point when you can start adding fish. There's no
"low" level of nitrite (with an "I"). Any nitrite
level above 0 is potentially dangerous, and above 0.5 mg/l there's
a good chance of the fish dying quickly.>
The tank is heated to about 79-80 degrees F.
<Too warm for Neons.>
I am concerned that the water may be too hard for them. When I tested
the GH it was 180ppm. Is the hardness hurting the fish?
<Can do, long term. But Neons won't die within days because your
water is moderately hard. In fact they may well do just fine, provided
everything else in your tank is good.>
If so, what can I do to lower it?
Jumbo Neon Tetras
Neons Eaten By Which Fish? 10/14/10
Question: We have an 80 gallon tank, with an old upside down catfish 5
inches long, an old striped Rafael 4 inches long, 2 new severum 2 1/2
inches long, 2 new angel fish about 2 inches long, and we had 15 jumbo
neon tetras about 1 inch in size that did well for three weeks and have
now been slowly eaten. Who would be the culprits in our tank? Could we
be successful with the jumbo Neons if they were 2 inches long?
< Real upside down catfish are only a couple inches long. There are
many Synodontis species that swim upside down and could be called
upside down cats. The cichlids could be killing them and the catfish
picking off the scraps. Larger fish would no be eaten right away but
still could be killed..Neons really do better in a tank with fish their
Neon tetra turning white, but acting otherwise normal,
likely NTD 09/29/10
I need some advice on my poor neon tetra.
Here's the aquarium history:
20 gal. planted tank with bog wood, fully cycled since February
Last tested last night using a Jungle test strip:
Nitrate - about 10 ppm (mg/L) (the colour was pinkish between
0-20 and within the 'safe' zone)
Nitrite - 0
GH - Soft, about 75 ppm
Chlorine - 0
KH - in the ideal range 120-180 ppm
pH - about 7.2
The last water change was about a week ago.
<All sounds ideal.>
Note: the bogwood had black fuzzy material growing on it, so I
removed it, scrubbed it, then boiled it in a 10% vinegar
solution. Then I scrubbed it again and let it soak in plain water
for several days before returning it to the aquarium last
<The black stuff is red algae, and scrubbing it won't make
much difference either way. Red algae tends to grow in conditions
where there is medium to bright lighting but not enough
fast-growing plants. Stick a clump of Floating Indian Fern in the
tank, and you should find algae becomes much less of an
Tank inhabitants: 1 rubber lip Pleco, 1 male Betta (he's
peaceful), 7 neon tetras, 2 assassin snails.
<All sounds fine, my one comment being that Bettas prefer
warmer water to Neons. Your Neons, Rubber Plec, and to some
degree the snails will do best kept fairly cool, 22-24 C/72-75 F
being ideal. Although not the reason your Neon is sick, this is a
common reason why Neons generally have relatively short lifespans
in many tanks, a couple of years instead of 4-5 years.>
The Neons are the latest addition, added back in July, and were
purchased from a reliable LFS (not PetSmart)
<Unfortunately with Neons, they mostly come from the same fish
farms, no matter where sold.>
The fish are fed once daily one of the following: Topfin Betta
food, Bettabites, Topfin tropical flakes, Topfin freeze dried
blood worms, and Pleco algae wafers. I usually rotate through
these. The only exception was back in early September, I gave the
fish a 3 day feeder block. I don't normally use the
<Very wise; they tend to do no more harm than good. Your fish
can easily go two weeks without food.>
All fish have been eating well, with some of the fish being pigs
and eating too much from time to time.
<Sounds like they're doing well.>
Here's the problem:
One of the neon tetras has recently, over the last few days,
developed a discolouration from the dorsal fin, through the
colour bands and now to his stomach. I think it started at the
colour band and has migrated out, but I could be wrong. The white
patches are not fuzzy. The fish appears slightly lumpy - not
looking nice and sleek like his brethren. He simply doesn't
<My fear here is that he's tending towards Neon Tetra
Disease. This is one or two distinct diseases: some people think
it's usually a parasite called Pleistophora, while others
thing at least some cases are caused by a bacterial infection.
Either way, Neons rarely if ever recover, so euthanasia is
usually the best approach. Pleistophora at least is highly
infections, and many, MANY aquarists have found that once one
succumbs, they lose another Neon every few weeks.>
However, the fish seems to be behaving normally - he is
schooling, eating, swimming well, reactive to a person watching
the tank. He is not restless or stressed looking, fins are not
clamped, not gasping for air, not glancing on
I have Googled my brains out and now just have a list of possible
maybes that each require different treatments. Is it
<This is usually distinctive, with growths around the mouth,
but to be honest with Neons being so small, detecting such
features is hard.>
Neon tetra disease?
<I fear as much. NTD is characterised by loss of colour, loss
of appetite, a tendency not to school with the other Neons,
shyness, bloating, and eventually death.>
Muscle death due to invisible parasites/flukes?? I just don't
<Nor do I.>
I will take a picture and send it as soon as I get home
<Very good, this will help. Do note our preference for a sharp
photo no larger than about 500 KB.>
My current plan is to buy a 2.5 gal kit with heater and filter to
use strictly as QT.
<That would be very wise. If handled this way, you might try
using a broad antibiotic and hope for the best. If you decide to
euthanise the fish, read here:
The clove oil method works extremely well with small fish, I
finding a litre of water with 30 drops of clove oil does the job
quickly and painlessly.>
I will take Mr. Yucky out tonight and await further
instructions... Please let me know if there is anything else I
can tell you.
<Hope this helps. Cheers, Neale.>
Neon tetra turning white, but acting otherwise normal 09/29/10
Thank you very much Neal for the quick response.
<Always happy to help.>
I will make some changes to the tank as suggested (always looking
for an excuse to add more plants). I also keep the temp at 76 - at
the high end for tetras and the low end for Bettas. I guess
nobody's happy.... maybe I should move the Betta into his own
<Would be wise.>
As for the sick neon: he was quarantined last night.
<OK; but if he's merely injured, this could cause stress,
and that in turn will make him less rather than more likely to get
I'd like to try medicating first as the fish doesn't appear
to be distressed as of this morning. However, I already own clove
oil and am prepared to euthanize if things don't improve.
My next big worry is this: what should I do with my main tank now?
Is there anything I can do to ensure that the others don't come
down with the same illness?
<Prayer? In all honesty, Neon Tetra Disease is very difficult to
eliminate from a school of Neons, and it's more about ensuring
optimal conditions and removing infected fish than anything more
I plan to do a water change tonight (the usual 20-25%) and
replacing the carbon filter (long overdue).
<Do bear in mind my usual advice that carbon removes medications
and is also fairly useless in freshwater tanks. If you don't
have a specific reason to use carbon, the space in the filter would
be MUCH better used for more biological media.>
Re: Neon tetra turning white, but acting otherwise normal
Sorry, didn't see the response to this email until after sent
the last one... see what I mean? Weird!
<Indeed. The thing with Neons and many other transparent fish is
that damage to the skin or muscles makes them opaque. If the whole
fish is opaque, that usually means they're very ill, but if
it's just a region,
then you may be dealing with something more like a bruise.>
This fish hasn't been touched by a human since he was first
placed in the tank back in July. Last night was the first netting
for him in a while. I was suspecting he'd been hurt by
decorations (the bogwood is kind of pointy in spots) or by another
fish, but wasn't sure.
<Bogwood shouldn't be a problem as such; Neons come from
habitats with lots of things they might bump into, yet manage just
fine. On the other hand, fish can bump into things -- including the
glass and hood -- when alarmed, including when lights are turned
on, so a good tip is to turn the room lights on a few moments
before turning the tank lights on. The reverse is helpful at night
when you're switching off the aquarium lights.>
I just fear having all my fish wiped out due to ignorance on my
<I wouldn't worry about that. For what it's worth, Neons
are one fish I've never managed to keep alive for long. The
quality of Neons in the trade is, unfortunately, rather
I'll keep him as is, isolated. I won't medicate for now. Is
there anything you'd recommend that I feed him for a faster
recovery - or just the same old flake?
Is a product like stress coat of any use in a situation like
<Won't do any harm, so if you have some, sure, use it. But I
wouldn't rush out to buy this or Melafix or whatever.>
Crossing fingers! Thanks again,
<Glad to help. Good luck, Neale.>