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| FAQs on the Zebra Danios Reproduction Related Articles:
Barbs, Danios &
Rasboras, A
Barbed Response; Wrongly maligned for being fin-nippers, barbs are in fact
some of the best fish for the home aquarium by Neale Monks
Related FAQs: Zebra Danios 1,
Zebra Danios
2, & FAQs
on: Zebra Danios Identification,
Zebra Danios Behavior,
Zebra Danios
Compatibility, Zebra Danios Selection,
Zebra Danios Systems,
Zebra Danios
Feeding, Zebra Danios Health, &
Barbs,
Danios, Rasboras 1, Barbs,
Danios, Rasboras 2, B,D,R Identification,
B,D,R Behavior,
B,D,R Compatibility, B,D,R Selection,
B,D,R Systems,
B,D,R Feeding, B,D,R Disease, |
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Danio Fry 8/30/08
Dear WWM Crew,
<Ave,>
My Danios laid eggs a few days ago. I removed all of the eggs and place them in
a cup temporarily. They hatched yesterday morning. They are against the wall of
the cup right now.
<Congratulations!>
Can you please tell me what I should feed them and when I should start feeding
them.
<Most fish fry will use their yolk sacs for a period of time post-hatching;
you'll see that they have yellow blobs on their bellies and don't actively swim
about. Instead they merely clump together, wriggling their tails to keep clean
water flowing over them. Once the yolk sac has been consumed, then they start
looking for food. In the case of Zebra Danios for example, this will be about
4-5 days after they have hatched.>
I read that when they came away from the wall that is when you should start the
feeding process.
<Correct.>
How do you make infusoria? I read that you make it by crushing green vegetables
(like lettuce) and add it to the water. You then let the water sit until it
becomes green (approximately 1 - 2 days).
<Pretty much. There are any number of methods using lettuce leaves and banana
skins. The key is putting the "soup" somewhere sunny, because it's the sunlight
that makes the algae grow, and the algae is what makes the infusoria grow. The
'Old School' method sped things up using Apple Snails, which for some reason
seem to speed the whole process up.>
Also, I read that you can feed them with an eye dropper or a baster. Can I also
chop up brine shrimp into little pieces?
<None of this is worth worrying about. Zebra and Pearl Danios are both easily
reared using liquid fry food (such as Liquifry) or finely powdered flake food
(such as Hikari First Bites). I'd tend to use the liquid food first, and the
flake food after 1-2 weeks. Really, your problem won't be feeding them, but
keeping the water clean. Baby fish need 4-6 meals per day, though those meals
should be tiny. A simple pipette (of the type that comes with fish medications,
for example) works great for adding food and slurping up uneaten food
afterwards.>
I am in the process of setting up a fry tank with a sponge filter, heater and
etc.
<Cool! Welcome to world of fish breeding... possibly the most rewarding (and ego
massaging) part of the whole hobby, fancy saltwater reefs notwithstanding!
Breeding and then rearing those fish to maturity is an objective test of your
fishkeeping skills.>
Also, how often do I change the water of the fry tank?
<As often as practical. If possible, use a jug to take some water out on a daily
basis. But at least a couple of 10-20% water changes per week would be
recommended. Does rather depend on the size of the tank, filtration, number of
fry, etc. If the water goes "bad" the baby fish will die quickly and in big
numbers, so be cautious and err on the side of keeping the water extra clean.>
Please give advice. Thanks for you help - Jean
<Cheers, Neale.>
Zebrafish Development, lit. searches,
scientific
7/17/2008
Hello,
I am currently working in a Cell biology lab that is using zebrafish as a
model system. What is the minimum temperature that a zebrafish embryo can
develop? I have read that adult zebrafish can tolerate a wide range of
temperatures (from 64-80F). I have also read that spawning is temperature
induced. Is it possible for zebrafish embryos to develop normally in
temperatures as low as 64F (since reproduction is stimulated by warmer
temperatures?)? If not, what is the lowest temperature that normal
development can occur?
Thank you very much for you time!
<Greetings. I'm assuming from your e-mail you're an undergraduate who's been
assigned a project at a research lab someplace. That's great. Now, I do
vaguely know the answer to this, but I'm pretty sure that putting into your
project a factoid gleaned from "some guy on the web", even one with a PhD
like me, isn't what your professors are after. What they want from you is to
do a literature research. Trust me on this: being a some-time university
professor myself, I know precisely and exactly what I expect from my
undergraduates. So, what I suggest you do is first find out the scientific
name of the Zebra Danio, and then use the bioscience/biomed literature
search tools (e.g., SilverPlatter) at your academic library to access the
scientific literature. Warning: the scientific name of the Zebra Danio has
changed at least once in the recent past, so you will need to use both names
to get the full overview. The developmental biology of the Zebra Danio has
been done to death, and it was something being studied decades ago. So the
answer to your question is certainly out there. Confused? Ask the librarian;
librarians are happy to help with focused questions like this and will know
precisely what tools are available to help you. In short: Good students use
the scientific literature; Weak students use Google and Wikipedia. It's as
simple as that. Good luck with your project! Neale>
Re: cichlids
Bob,
Hi, my name is Brenee King and I am a students of Mr.. Nordell's.
I was
considering doing a project with Cichlids (Zebra Danio ?)
<Hmm, Zebra Danios? These are actually not cichlids, but cyprinids (egg
laying toothed carps, Brachydanio rerio I think is still their valid scientific
name>
having to do with their familiarity effecting their mating habits and wanted
to know how often I could expect them to mate? Also how long it takes for the females to complete their cycle, mating and having their children? Please contact me when you have a chance. Thank You for your time and considerations.
<Do put this fish's name in your search engines, go to a college library with
the same... and start developing your working bibliography on this species
biology. See the pieces on the site www.wetwebmedia.com
on how to search the literature.. You will have more questions, need more
answers than you have asked for here. Bob Fenner>
Zebra Danio Q 3/10/06
Hey Bob!
<June>
My fiancée and I are looking forward to seeing you at IMAC (we actually met at
IMAC last year and are getting married this June).
<Congrats!>
Any way, I'm currently working for a research lab that is working with zebra
Danios
<A fave test animal species in the sciences>
(ophthalmology research) and I tend to keep the pH at about 7.2-7.6, but one of
the ladies that works in the lab says that's too
high and that their eggs are becoming coagulated (just with in the past 2
days). She thinks that it's because of the pH.
<Mmm, is possible... do you know the corresponding alkalinity? Might be better
to blend more/some "just water" in the system here>
Now, I have my degree in marine biology, and take my water chemistry results to
heart, and to
have someone double checking my results is insulting to me, so that is why I am
e-mailing you to see what your opinion is. The PI of the lab
trusts me very much and hold me in high regard, but for some reason these ladies
seem to not trust me. Go figure.
<They may have practical experience going for them here...>
Any info you can give me would be very helpful as then I can have someone who
has even more experience backing me up. :-)
Thanks again!!
June
PS: Didn't know which e-mail address to send to, so I sent to both.
<Ah, no worries. Bob Fenner>
Siphoning Babies - Danio Fry and Gravel Cleaning - 09/30/2006
Hi Crew,
<Hi, Mike! Sorry for the delay.... your email wasn't able to come through
properly in our Webmail system; my computer was able to read/respond, but I've
been out a bit. I do apologize for this delay.>
I spend far too long reading your website but enjoy it immensely.
<Heh! Me too.>
I have a mature 240 litre freshwater community tank and over the last few weeks,
every time I do my weekly partial water change, I syphon tens of baby zebra
Danios out with the tank cleanings. Obviously they are too small to net and I've
tried various methods of separating them from the muck but, inevitably, I spend
hours every week with my head in a bucket rescuing baby fish by whatever
painfully slow method I've invented; dipping cup, air-tube syphon or pipette
usually.
<How about a brine shrimp net?>
My problem is that I'm becoming increasingly fond of dumping the baby laden
sludge directly into one of the fry tanks to save time. Although it's probably
very good baby food, it does mean that I am building up waste in tanks that I
can no longer syphon 10% of the water out of weekly since I'm back to square one
- babies and muck. So what, if any, faster methods can you suggest of separating
the babies from my siphonings please
<A pipette and patience is probably the best/safest way....>
and what is the best way of cleaning the gravel in the fry tanks?
<Best option here is not to keep gravel in your fry tanks. Keep them
bare-bottomed instead, if possible.>
On a marine note, have you seen the new marine shop/website in Leeds? www.reefranch.co.uk
http://www.reefranch.co.uk/ ?
<I haven't; I don't think anyone on the Crew right now is in the UK - but if I'm
out that way, I'll have a look!>
Fantastically well cared for fish and corals.
<Sounds great. I like to hear of new, good shops opening up.>
Best regards,
<To you as well!>
Mike Cursons
<Wishing you well, -Sabrina>
Breeding my Zebra Danios
8/10/07
I have a male and a female Longfin zebra Danio. I want to breed my Danios
and the female appears to be full of eggs, but she seems uninterested in the
male. I have a breeding tank, but I am not sure how to breed them. Can you
please give me some advice?
Thank you.
<Greetings. Breeding Danios is not usually difficult. But as with any fish, you
need to get the conditions right. You want slightly soft to moderately hard
water, and the temperature must not be too high (about 22-24 degrees C) is
ideal. Prior to spawning the fish, you should keep them cool, around 18-20 C,
for a couple of weeks. Then warm the fish up, and start feeding lots of live or
wet-frozen foods, perhaps 3-4 times per day. This is called "conditioning", and
what you're doing is tricking the fish into thinking it is the breeding season.
In the breeding tank, cover the substrate with glass marbles or small pebbles.
What you want to create is a tank bottom where the eggs can sink safely out of
reach of the parents. For spawning to occur, you need to add a small group of
males and females, ideally slightly more males than females. It has to be a
group, not a pair. These fish spawn in groups. Once they've spawned, you can
remove the parents. The eggs hatch in about one day, but it's another 4 days or
so before the fry are swimming about looking for food. Give them infusoria or
commercial baby fish food (of the egg-layer, not livebearer, variety). The fry
grow quickly and are basically hardy and easy to rear. Danios are among the best
egg-laying fish for a first breeding project, so you should find them quite
rewarding. Cheers, Neale.>
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Are my Zebra Danios Pregnant?
– 10/28/07
Hi,
I just bought 22 fish: 4 guppies (2 girls, 2 boys), 3 zebra Danios, 3 red eyed
tetras, 9 neon tetras, and 2 mini catfish. They are all in one 30 gallon tank.
Everyone has been getting along. One male guppy died, but now my 3 zebras have
gigantic bellies. I didn't buy them like that and I have had them for about two
weeks. How do you tell male and female apart for zebras? You see, I am 11 and my
dad helped me put a tank together and tanks have been in the family for years.
My dad and friend thinks that they may be preggers. But I am new breeding and I
have only breed my guppy which had 4 babies. I don't want to start egg breeding.
What should I do?
-Thanks!
Sarah
<Hello Sarah. Danios don't get pregnant. But they will fill up with eggs prior
to spawning. Males tend to be slender anyway, and a more yellowy colour; females
are rounded and tend to be silvery. Danios are easy to breed, and are often
considered the ideal species for beginner's to start with. If you want to breed
them, you'll need to put pairs by themselves in another tank and let them
scatter their eggs on the ground and among plants. Once they're done, you put
the parents back. The eggs hatch after about 1 day, and the fry can be reared on
liquid fry food. They grow quickly. If you don't want to breed them, don't worry
about it. They'll lay the eggs, and the eggs will be eaten by other fish. Do
check you aren't overfeeding the fish. Fish will also swell up when sick, though
for three to do so at the same time is unlikely. Good luck, Neale>
... uh... FW... breeding...
Danios? Zebras... 10/28/07
Hi,
I e-mailed you guys earlier and I got a very good answer so I will come to you
for now on. Well, you guys told me to put the parents in a separate tank and
when they gave birth, to put them back in the big tank. The problem is I don't
have another tank and I already went over my "fish" budget.
<Ah, a common problem! There's really no workaround. Fish eggs are small and
tasty (caviar!) and when dropped in a community tank other fish eat them. So
you need to put the parents somewhere else, so you can remove the parents after
spawning and protect the eggs yourself.>
I also said that I didn't want to breed the zebra Danios. I really want to, I
just don't know how.
<Find an aquarium book on your next trip to the library; most will have a
section on fish breeding. Danios are quite easy to breed. There's nothing
difficult about doing it. You just need to be patient and follow each step in
turn. Fish breeding is one of the best parts of the hobby. Watching a baby fish
grow from an egg to an adult is a true wonder. If you don't have another tank
right now, then save up and get one some time down the road. Danios live for
several years, and the bigger they are, the bigger the batches of eggs you will
get!>
As I said in my other e-mail, I didn't know if my zebras are boys or girls, but
now I think that they are all girls.
<Oh dear.>
But, I never bought them pregnant.
<They aren't pregnant. They may simply be fat, or they may have eggs inside
them. Without a male, they won't breed (obviously!).>
So is it possible that my Male guppy mated with them also?
<No. A Guppy is as distantly related to a Danio as a Gorilla is to a Tiger.
Completely and utterly different. Guppies are livebearers (they give birth to
live babies, like humans do) while Danios are egg-layers (like birds).>
I have never seen him chase the zebras around. Could my red eyed tetras had
mated with the zebras?
<No.>
please help!
-Thanks!
-Sarah
<Just keep watching, learning and reading. Buy/borrow a book about aquarium
fish. There's too much to put in one e-mail. Breeding fish is terrific fun, and
warmly recommended as a hobby. Good luck, Neale.>
Ongoing Brachydanio repro....
reading 10/29/07
Hi,
Do you guys think I could put just one zebra with a big belly in my breeder for
a while?
<No. For one thing it'll get stressed. Secondly, it'll probably jump out (or
smash itself to pieces trying).>
Because it is only a box with a "v" divider that can be taken out. How do I know
if they are only a couple of days away from giving birth?
<As I said in the last two e-mails -- Zebra Danios DO NOT GET PREGNANT! They lay
eggs. They eggs will come out regardless. In a community tank, the eggs get
eaten unless you find them quickly and rescue them. You can put the eggs in a
breeder.>
I mean, if they are pregnant I don't want them to give birth and then all the
babies get eaten.
<They won't 'give birth'. The eggs are dropped on the substrate. The eggs hatch,
baby fish emerge, and for the first 24 hours or so basically don't do anything.
After a day or so, the baby fish start swimming. In a community tank THEY WILL
get eaten long before that happens.>
Because I also want to see them grow up.
<Hence the need for a breeding tank...>
-thanks for your time and effort for me to have successful breeding!
-Sarah
<Read up on fish breeding. It's fun, and quite easy. But there's no "short cut".
You need a second tank for egg laying fish. Goo luck, Neale>
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Pregnant Zebra Danio 10/2/07
Hello,
<Hi there>
I have a 55 gallon tank with a 13 inch ?Plecostomus,
<Yikes! Needs more room... or to be traded in for a smaller individual>
3 zebra danios(2 females, 1 male).? My? problem is with one of the female
Danios.? She appears to be very very pregnant.? She is huge.? Her skin appears
to have cracks? running down the side and underneath her belly.? She is eating
and swimming.? She will not release any eggs.? I am assuming that is what she
should be doing. Do you have any advice on what I could do to help her out?? It
looks like she is going to explode.
Thanks,
Julie
<Likely some sort of gut blockage... what do you feed and how? Please read here
re possible Epsom Salt treatment:
http://www.wetwebmedia.com/FWSubWebIndex/saltusefaqs.htm
Bob Fenner>
Re: Pregnant Zebra Danio... Lg. Pleco in
small world 10/3/07
Hello,
<Hi there>
Thank you for your reply about my problem with my pregnant Danio.
<Welcome>
However, I was taken back by your response to me having a 13 inch Plecostomus in
a 55 gallon tank.
<Yes... the fish is as long as the width of this tank...>
I don't have the tank over loaded with plants or decorations so he moves around
easily.
<Mmm... do you know which species of Loricariid this actually is? There are some
that would/might be stunted here...>
I see him swimming on his side, upside down, enjoying the bubble curtains -
eating the algae all over the tank. He "appears" happy and able to move around
freely. I have moved him from a 10 to 20 to 55 gallon tank as he has grown from
2 inches to 13 inches in the last 4 years. I am a novice at the Plecos and
didn't have any idea of what I was getting into.
Could you explain this to me in a little for detail please - this fish has
become a part of my family - my husband thinks I love the fish more than
him (haha)- as I sit and talk to the fish and just watch the fish's personality
unfold daily.
Thanks,
Julie
<Do take a look on fishbase.org re the family... some of the species listed...
This fish really does need more room still. BobF>
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Zebra Danio egg question
12/31/07
Hey,
<Hey?>
When I went to go feed the fish this morning I noticed some small black dots an
my live plants. Could they Be Zebra Danio eggs?
<Possible but unlikely. Fish eggs are usually 1 mm or so across, transparent,
and with a jelly-like appearance. As they mature, you should soon see the
embryo. By all means remove the eggs and place in a floating breeding trap to
see what happens. But there are other things they might be -- snail eggs,
planarians, silt, etc.>
-Thanks!
-Sarah
<Cheers, Neale.>
Re: Zebra Danio egg question
12/31/07
Ok,
You said to put the black things in a breeding trap. I am borrowing one from a
friend and right now it has 12 baby guppies in it. Will the guppies
eat them?
<Certainly possible. You could improvise a breeding trap of some sort using a
plastic cup with some small holes punctured through it to let water diffuse in
and out. Use your imagination. What you're after is something that floats, keeps
the eggs safe, but allows for a slightly flow of water without the holes being
so big the baby fish (if any) would escape.>
I'm also wondering, could it be a different kind of algae?
<Maybe. Without a photo, "small black spots" are difficult to identify.>
There doesn't seem to be a jelly-like substance around them. And they are at
least 1/4 of a centimeter apart.
<Doesn't sound much like fish eggs.>
-Sarah
<Cheers, Neale.>
Re: Zebra Danios egg question
12/31/07
Hi. I tried to take a picture. see what you think. Thank you. Sarah
<Hello Sarah. Not sure at all what these are! They don't look like
Danios eggs to me, but who knows? Could be some sort of insect eggs. Out
them into floating thing and see what happens. Keep us posted! Neale.>
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