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FAQs on Oscar Reproduction/Breeding

Oscars spawning and fighting badly. 7/28/07
hello I have two Oscar's about 2yrs old. they spawned about a month ago all the usual stuff occurred no fry were produced, just a fuzzy mess.
<Almost certainly either [a] the eggs were not fertilized because the fish didn't spawn properly this time or [b] more likely they were fertilized but water quality was poor and fungus took over the batch. It's important to keep water in the breeding aquarium spotlessly clean and to ensure there is ample water movement across the eggs. Adding anti-fungal medication is also useful if you decide to "pull" the eggs are raise them yourself.>
last night they started fighting after a tank change two days ago (20%) nothing abnormal figured here we go again. there is a Pleco and red eared slider who is in love with the tiger Oscar lol. took them out.
<Strange combination to begin with, but okay...>
and with in an hour my albino has ruined the tiger who I presume to be the female as she is smaller and stuck by the eggs nonstop last time.
<Well, obviously they are no longer compatible. You will need to separate them, and if you do decide to re-introduce them, use the egg-crate tank divider method to begin with so they can see but not attack each other for a couple of weeks.>
her sides are thrashed her gills have a chunk missing and her fins are strings. so I divided them hopefully in time.
<Let's hope.>
A) will she heal ok and what preventive measures should I take to help?
<Yes, she will heal, provided you treat the water with anti-fungus/anti-Finrot medication RIGHT NOW and keep water quality PERFECT. We're talking 50% water changes every day for the first week, and then 50% water changes _at least_ weekly thereafter. With this amount of damage she's a sitting duck for every opportunistic pathogen in the tank. Take no chances, and cut no corners.>
b) will they still produce and fertilize? I guess its possible I have 2 females but not sure yet. the tigers lower belly is long and swollen downwards.
<Two females spawning together does happen. Sexing Oscars by eye is impossible. Can't be done. The only clue is the shape of the genital papillae, but you have to actually watch them spawning to see it. Everything else, like the shape of the belly, is myth not science.>
c) will the missing scales and cuts regrow. they were so beautiful.
<Yes, scales grow back.>
please help.
<Hope this helps. Please, next time, try using capital letters in your messages. Makes them easier to read. Cheers, Neale.>

Oscar gender 7/14/07
Hi:
<Ave!>
I have two great looking 9 and 10 inch red Oscars and until recently were inseparable. Suddenly they started fighting so I separated them by using a drilled piece of Plexiglas to divide the tank (75 gallon).
I would like to know if I have a mating pair or two males or females. Is there a sure-way to tell? and if I do have a mating pair, how can I encourage them to re-bond rather than fight?
Best Regards
Francisco Toro
<Oscars cannot be sexed reliably. All Oscars are mutually antagonistic towards one another once they become sexually mature, even males and females. There's no way to know you have a mated pair until they spawn together, and no, there's nothing you can do to change their minds if they don't like each other. The only foolproof method for getting a pair is to raise 6 and pull out the 4 that don't pair off. Be sure and read this: http://www.wetwebmedia.com/FWSubWebIndex/oscars.htm plus the connected FAQs on oscar reproduction. Cheers, Neale.>

Re: Oscar gender 7/16/07
Thank you very much for your feedback. I will keep up the wall (much to Pink Floyd's dismay...;-)
Best regards
Francisco
<No problems. good luck with your Oscars. Cheers, Neale>

Convicts and Oscars, repro.   3/14/07
Hi,
<Hello>
I stumbled across your website during a google search and I found it very informative, however there are questions that I would like to ask about our convicts and Oscar fish.
<Okay>
Firstly, we have an adult size Oscar and recently introduced a much smaller Oscar into his tank.  These two fish interact with each other extremely well and we were wondering how we can determine if we have a breeding pair...
<Mmm, they'll make this known in time... by successfully reproducing... There is such a thing as two females laying eggs together...>
they seem very playful to each other and are always rubbing against each other but we would also like to know how we can tell the difference between a male and female Oscar?
<Posted... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/oscarreprofaqs.htm
and the linked files above>
  A friend told me that you can tell the male from the female if their tale fin and dorsal fin overlap.....I have done heaps of research online and I have never come across this information....is their any truth to it?
<Mmm, some... the unpaired fins on most Cichlid species are longer, more pointed in males than females... but individual care, early life history can alter appearances...>
Secondly, we have a pair of convicts which every couple of weeks lay eggs that never hatch.  This has happened about 4 times now.  The first couple of times the female ate the eggs but more recently the some of the eggs turned a "yellow" colour and then these little worm like creatures appeared all over the eggs.  The eggs have since been eaten but the wormy things still remain.  Can you tell me what this means and what we need to do to get our convicts to breed properly?
<Mmm... May be that there is some creature in your tank interfering here... I would move these fish to another system, and dump, clean the present tank... Perhaps bleach wash it and its contents... See WWM re>
Thanks so much for your time...
Peta and Simon
<Welcome. Bob Fenner>

Egg Bound Oscar Is Probably Sick - 10/25/06
I have a female Oscar who is VERY full of eggs. She is acting very strangely and differently than the times before. She is almost just floating and hardly moving on her own at all. She looks like she's about to explode but only in her bottom. No swelling is apparent in the head or dorsal fin area.
She's been nose-first in the tank almost all day. We don't want to raise any newborn Oscars, we just don't want to lose her. Will it hurt her worse if a small amount of pressure is applied to her abdomen just to get the eggs moving out? I'm at a loss here and scared of my fish dying. Any help or suggestions would be greatly appreciated.
< She probably has an internal infection and is not egg bound. Do a 50% water change, vacuum the gravel and clean the filter. Treat with Metronidazole and Nitrofuranace
or Clout. This is best done in a hospital tank. Do not squeeze the fish as this may force pressure on the internal organs and cause problems. The key to a successful treatment is to treat early. You may already be too late.-Chuck>

Breeding Oscars - 09/07/06
Hi crew, I just bought a pair of Oscars. They are about 4 inches. I wanted to know what is the best way of sexing Oscars? And at what size they can be bred? Thanking you
< Oscars are very difficult to sex. Males may be slightly larger and the fins may be slightly elongated too but not by much. Experienced cichlid keepers look at the ventral openings and refer this as "venting". You are looking for differences in the actual openings. Females would have a larger opening to lay eggs. Males would not need such a big opening so it is smaller. Since Oscar eggs are very small it is not a very reliable way to tell the sexes apart. Bottom line -almost impossible. They start to breed when they are around 8 inches. Sometimes smaller.-Chuck>

Breeding Oscars 07/04/06
Hi I have searched over your web site and there is a ton of info  that I've learned. But I do have a question that I couldn't find an answer for. I  have a
55g tank with (I know there are too many fish) 2 Oscars a pacu and 2  Dempseys.
I have had the fish in the same tank for about a year. My Oscars are  about 7 inches. One Oscar has been hiding behind a rock and when the other comes  up
they start going at each other with there mouths wide open. Also I just   noticed 2 holes in the gravel like they were starting a place to lay eggs???? I
REALLY HAVE NO IDEA HOW TO TELL THE SEX OF MY OSCARS???? CAN YOU PLEASE INFORM
ME OF HOW TO DO THIS??? AND OR MAYBE YOU KNOW WHAT'S GOING  ON?
< Sexing Oscars is very difficult. Some experts look at the vent area. The male will have two holes that are about the same size. The female may one vent hole larger than the other. Watch when they spawn. One will have a larger tube. That is the female laying eggs. Both parents will guard the eggs and chase/kill all the other fish. At 80 F the eggs should hatch in three days. In three more days the fry will need to be fed some baby brine shrimp or microworms. At this stage they should be removed to their own tank as the parents may be getting ready to spawn again.-Chuck>

Re: Breeding Oscars? 07/04/06
So from the info that I've given you do you think they are getting ready to   spawn?
< You fish are still relatively young, but the observations you reported could be a prelude to spawning.>
The fish keep going at each other with there mouths wide open?
< Occasionally cichlids will lip lock as a sort of test of strength to see if a potential mate is suitable.>
<Digging holes and hiding in the corner?
< If they are not pairing up, then one is becoming territorial and has bullied the other one into a corner. Digging holes in the gravel is a way to establish a territory.-Chuck>

Sexing Oscars   1/10/06
Thank you for the advice. Which is easier to take care of: males or female and how do you tell the difference between the two? Jess
< Oscars are very difficult to sex. The males may get slightly larger than the females but that is about it. Very large fish may be vented. This is done by turning them over and looking directly at the ventral openings. The females vent will usually be larger than the anus while the males vent may be the same size or smaller. I am sure the pro breeders in Florida Fish Farms can tell right away but they probably have been breeding Oscars  for years. there temperament is about the same for both.-Chuck

New to Oscar Breeding: A few Questions 6/31/05
I was at a fish store this weekend and saw a very lovely pair of what I was told Breeding Oscars.
<Great find! Breeding pairs of Oscars are decently hard to locate!>
I have raised Oscars off and on for some time now but never a breeding pair and normally in smaller form one at a time.  I was
wondering if a 90 gal tank would be a suitable size for the pair.
<Indeed, a 90 gallon is ideal for a breeding pair of Oscars.>
The store has them in a 70 gal. But I really want to help them and take care of them the best I can.
<That's always great to hear! Good job at being a responsible fishkeeper!>
I am even looking at acquiring a 210 gal later on to accommodate them if I was to get them.
<It could probably also accommodate another breeding pair or several other large cichlids, if you wished.>
Anyways my second question is to tank setup.  What do you recommend.  I have
herd using gravel, no gravel (with Large Slate for spawning), Or rocks or no Rock.  Please advise so I can do the best for them.
<I <i>always</i> go for the natural environment for all of my tank setups, and I would recommend the same, even for a breeding pair. Tank setup is a very subjective factor, and there are many opinions on how to do it "best." I think you should research it on your own and decide what you like best and what would benefit your goals best. Good luck! Mike G>
Josh

Sexing Oscars
Would it be easy to vent an Oscar of about 5-6  months?
< No, Oscars are one of those fish that can be difficult to sex. The older the better. They take awhile to become sexually mature. Even experts have problems sexing these guys.>
How do you keep them from wiggling out of your  grasp?
< Siphon 5 gallons of water out of your aquarium into a bucket. Take a bath towel and cover the bucket. Push the center of the towel down into the bucket about half way to the bottom to create a little wet area. get the Oscar and place him inside the towel in the water. Then lift the towel while cradling the Oscar in the wet towel. At this time he can be turned over and held in the wet towel.-Chuck>

Breeding Oscars?
Hello! I am now seeking your help once again.
I am having trouble with my smallest Oscar!!!!  Now, I have 3 Oscars in
total, and the 2 of them are big both ranging from 10-12 inches in length if
not bigger.  My small one is about 8-9 inches and is acting funny.  Lately
they have been fighting.  Now, my boyfriend went to clean out our 77 gallon
fish tank and the little one keeps trying to attack him, but the bigger ones
stay in a corner and don't go near him.  My boyfriend also put the towel up
to the glass and he tries to attack it through the glass, and the funny
thing is that he tries to eat the vacuum that is cleaning the tank.  He has
never done this before, and we have had them for a long time.  Why the
change so soon? What do you think is wrong with him????  Is he bored?  If so what can we do
to make him unbored??  What other reasons could he be doing this as he never
did this before. All of our fish get along perfect, except for the odd fight.  We have had
them for a long time and now he is acting weird.  If you could e-mail me
back ASAP that would be great as I am lost and am having a hard time
understand what he needs.  My fish are like my children, I love them and
well do whatever I can to help them. What could be wrong with him??
Thank you for your time!  I look forward to hearing from you soon as your
advice seems to help whenever I need it.  Thank you once more! Courtney
< It could just be a case of getting ready to breed. The smallest one may be a female. After a period of time she has matured and is looking for a mate and is guarding a territory. Males are usually late bloomers and one of them will come around in time. When they decide to pair up then two of them will start to pick on the odd fish to the point that they may kill him. Remove the odd fish to save him. The pair will probably never let him back in the tank. The pair will clean off an area to lay their eggs. The eggs will hatch in three days and the fry will become free swimming in another three days. At that point they need to be fed. After two weeks the fry should be removed or they will be eaten by the parents.-Chuck>

Jermar's baby Oscars
Hello, my name is Jermar.
<Hello Jermar, Mike G here>
This is my first time on your web site and I must say it is extremely helpful and resourceful.
<I'll agree with you there.>
I recently purchase two (baby) tiger Oscar fish both are about (3" inches). I've had them for about three days. there great fish but they beg a lot. My questions are simple and I'm almost embarrassed to ask but, I'm new to keeping fish as pets there are my first. I would greatly appreciate some simple starter tips.
<I'd be happy to answer your questions.>
(1) I want to know some tips to cleaning my tank like, how! And how often to clean the tank {10 gallon}.
<Whoa, hang on... 2 3" Oscars in a 10 gallon tank? With such a set up, you are just begging for trouble about as eagerly as your Oscars beg for their food. As for cleaning a tank with such a heavy fish load, I would recommend removing and gravel, sand, or other decor to help prevent the accumulation of debris in hard-to-reach places. This will also facilitate cleaning and removal of solid wastes. I would recommend enlisting the help of a large filter rated for much larger tank sizes than 10 gallons to allow a bit of leeway if you miss a water change, which I think should be done every other day at around 25%. Oscars produce massive amounts of waste material for their size, and simply will not do well for an extended period of time in such a small tank without regular large water changes and much thought to maintaining the water quality within an acceptable range. Purchasing Ammonia, Nitrite, and Nitrate test kits could save you a lot of hassle in determining how clean their water is.>
(2) I have 2 small baby Oscar's in a 10 gallon tank, I know I have to get a larger tank, how soon should I get it, and what size should I purchased? ( the Oscars are very small at the moment both are about 3" inches now, very active and eager to eat).
<Ah, it is refreshing to hear that you intend to purchase a large tank when necessary. Honestly, I would recommend that you purchase a larger tank now. I would say that the bare minimum size tank would be 75 gallons, as I tend to like to take into account the adult size of a fish rather than its current size when determining an appropriate tank size. In a tank of 75 gallons, I would anticipate much growth in your Oscars. In a matter of months, I think they would be quite large and make such a tank look fuller. Of course, 75 gallons for small fish ca get boring, so you may decide to stock the tank with other similarly aggressive fishes, preferably cichlids. But please remember to keep the stocking densities low and to research any new purchase before it is brought home.>
(3) I've used your web sites "FAQ's" to find feeding tip's for small Oscars, But how often should I feed them? I gave them 14 guppy fish yesterday they ate all of them with in 30 minutes I haven't feed them today and I'm very worried about over feeding. Please help?
<I am not a fan of using feeder fishes as a source of nutrition with predatory fishes such as your Oscars. The risks of transferable disease are extremely high, and many of these fish have very little, if any, nutritional value. This is because they are kept in absolutely horrid conditions while they await being purchased. I am positive that your Oscars would accept pelleted or frozen foods specifically formulated for them, and would do better on such a diet. Hope this helps.>

Breeding Oscars
hi
I've e-mailed you a bunch of times about althea (my red Oscar),, well she now has a new friend, Jed (tiger Oscar) ,,is it possible that they will mate and bare children??
<Yes... possible... these are two varieties of the same species>
I've noticed a lot of odd behavior from both my fish., the tiger Oscar will vibrate its tail (kind of like what a alligator does when its ready to mate) and the nibble at each other also. and they wont leave each others side.
thanks for the help
Mike
<Do keep your eye on them... as Oscars can "turn on each other", becoming overly aggressive... trying each other out physically... and require you to either separate them into two tanks or with a divider. Bob Fenner>

Oscar Breeding

Thank you Chuck!
They are separated just like you said, have been for two days now. They look at each other through the divider.
Is there anything I can do about them not eating?
< Big cichlids usually don't like to be disrupted and may fast for a couple of days. Try washed earthworms to get them going.>
I am putting the vitamins in the water which are supposed to help enhance their appetites. The tiger just lays at the bottom of the tank and is not swimming around much. He isn't beat up enough (as far as I can tell) to not be able to swim.
So, they will still be able to "mate" separated?
< Yes. As long as they can see each other and there is circulation in the tank, some of the 1000's of eggs will be fertilized.>
Any idea how long I have to leave them separated?
< I would not put them back together until they are both eating well and are active again.-Chuck>
Thanks again.
Joey from Alaska

Oscar Breeding, More Follow-up
Another question for you, and this is an odd one...
How long will it take for my Oscar's teeth to grow back in?  Now that the mating pair is separated and I'm medicating, my tiger Oscar's damaged flesh has sort of fallen off and has revealed that in the process of their brooding, his upper lip was so damaged that it has sort of come off.  Very sad site to see.  He had a pretty decent under bite before this all happened, so this doesn't surprise me.  But, his teeth lie just under that lip and I noticed that he only has 2 left.  This is why he is not eating I suspect. Not even interested so much in blood worms.
Any idea how long they take to grow in?  I am medicating and watching him very carefully and there does not appear to be any infection.  Just a lot of facial damage.
Hope you have an idea.  This is probably one of the stranger questions you get.  Even a ballpark figure would help so that I know what to sort of suspect.  Poor fish!!!
< The teeth actually play a very small role in the fish's ability to eat. Once the gums and lips heal over then the appetite should pick up. Add some vitamins and keep the water clean to promote a quick recovery. White flesh is a sign that it healing. White cottony growth is fungus and needs to be treated.-Chuck>
thanks again,
Joey from Alaska

Oscars determining the sex of Oscars
Could you please tell me how to determine what sex are my Oscars.
Characteristics of the different sexes.
thanks,
Linda
Perry
< That is a great question, one I have been meaning to ask for a while now. There are a few ways to sex an Oscar. One is to wait for the Oscars to pair off, spawn, and watch to see which one lays the eggs. The second way is to remove the fish from the water, flip them over and compare their vents. I found a picture of someone doing it at the following link
http://www.petsforum.com/personal/svoorwinde/Oscars/oscars.htm
The above method does not sound like much fun to me. My Oscar (Buster) gets mad when I try to rub his belly. I asked Anthony about it and he told me the best way I have heard of yet. Below is what he said.
“there is an easier way: when most cichlids are first fed they will briefly express (extend/drop/flash/whatever) their "stuff". The ovipositor of a female is quite blunt and obviously wide enough to pass an egg through. Males have a pointed and tapered protrusion which generally is not extended as far as a females. Feed some tasty earth worms or small ghost shrimp to get them in the mood if necessary. When you are comfortable sexing African cichlids... you can apply this too to some Central and SA cichlids by looking for thicker lips and a larger buccal (chin) cavity on males”
Hope this helps- Gage>

Longed Finned Albino Oscars
Sir, PLEASE HELP ME!!! I have two Longed Finned Albino Oscars in a four foot tank. The larger of the two is about 14 inches long, the smaller is about 12 inches. I believe that they are about 2.5 years old and we hope that are a breedable pair.
<Do keep your eyes on them... this is a very small tank for such mature specimens and things can go sideways quick should they start fighting>
I have seen lip locking and some very industrious rock cleaning. The rock is a flat piece of slate. The larger fish does occasionally move small amounts of gravel. The smaller of the two Oscars laid eggs approx 12 months ago so I know that I have at least one female. The other fish showed no signs of interest.
I feed them mainly with barramundi pellets and live fish and occasionally crayfish. I am disappointed that they have not bred. Could you offer any suggestions to push along the process? e.g. water temperature, PH level, hardness, water quality, water changes.
Thank you for you time, Brad.
<It's possible you have two females... and there is a hard fact I must convey. In order to keep the price and availability of these hybrids controlled, the folks who produce them in the Far East try to sterilize them (with high temperature, chemicals)... so breeding pairs outside the area are exceedingly rare. Care is per the "regular" Oscar, Astronotus ocellatus: pH range: 6.0 - 8.0; dH range: 5.0 - 19.0 temp. 22-25 C. Best to condition pairs, keep together, with large, regular water changes. Bob Fenner>

Rare Spawning Oscars
please could you answer a couple of questions for me. firstly is it ok to have my 2 Oscars in a 350 L tank?
<Yes, certainly to both>
how many could I have?
<Two would be a good number for once they're about full size>
secondly in my 4 foot tank is that big enough for a Volitans and a Odonus niger?
<Should be... just assure the Lion isn't large enough to swallow the Trigger when the latter is small, and that the Trigger doesn't harass, deprive the Lion of food when it is larger>
the tank holds about 210 L both English litres the marine tank is run by a Fluval 303 and an AMiracle trickle filter and also another Fluval with a uv sterilizer attached to it.
thanks for your help
Alex
<Be chatting my friend. Bob Fenner>

Oscars (spawning, rearing)
I emailed u before about my tanks. my question for you though is that my Oscars just had there first spawning in the Trigon 350 and I am a little unsure if to leave them in there as there is a plec and a catfish in the tank.
<If this is the first or second, third spawning, do leave them all be as they are now... too traumatic to be moving any, all fishes, young around. And this tank is big enough to allow the "plec and catfish" to get out of the Oscars way... and run away. In a few spawns, I would utilize an easy to remove spawning medium (like a large clay flower pot, piece of slanted slate... and remove this to a rearing tank... Do start studying up about these affairs, planning on space to raise whatever number of young you think you might want... raising foods for them... Bob Fenner>
do u think I should set up another tank or leave them with their proud folks any help would be much appreciated
Alex

Fuzzy Eggs
My red tiger Oscar has laid eggs, 2days later the eggs turned into a white cotton-like substance. This is the first time they have laid eggs and I don't know what to expect .I am a first time Oscar owner I have had them for a year now. please help Mr. Curious
<The white cotton-like substance, or fuzzy stuff, is most likely a fungus from the infertile eggs, or dirty water, they are rather messy fish. I would use a small siphon tube to suck out the bad eggs and the fungus. If you were to remove the good eggs to a separate tank some Methylene blue could be added to the water to help prevent the fungus. Best of Luck, Gage>

Fertilizing Oscar Eggs - 8/15/03
Can Methylene blue be used to fertilize Oscar eggs.
<Hmmm... I'm wondering if you mean to ask if it will prevent fungus from developing on the eggs? If so, yes. I'm assuming you already have a female that laid the eggs, and a male that fertilized them... and now wish to improve the chances for a successful hatch. Anthony>

Fuzzy Eggs
My red tiger Oscar has laid eggs, 2days later the eggs turned into a white cotton-like substance this is the first time they have laid eggs and I don't know what to expect .I am a first time Oscar owner I have had them for a year now. please help Mr. Curious
<The white cotton-like substance, or fuzzy stuff, is most likely a fungus from the infertile eggs, or dirty water, they are rather messy fish. I would use a small siphon tube to suck out the bad eggs and the fungus. If you were to remove the good eggs to a separate tank some Methylene blue could be added to the water to help prevent the fungus. Best of Luck, Gage>

Oscar Eggs
Thanks gage, but it has spread over all the eggs. (unable to save any)
<bummer>
I don't know ! maybe I have 2 females <it's possible> and then again maybe not. as I'm typing I looked over at the tank and they have begun to lip lock all over again and change in color a bit with their mouths open.
<sounds like flirting to me.>
HOPEFULLY NEXT TIME MR. CURIOUS
<I might consider a second tank to move the eggs to. -Gage>

Pairing Oscars
Hello;
I love your site as it has been very helpful to me in the past.
<Thank you, I'm glad we could be of service.>
I just bought two Oscars and I was trying to figure out if they had paired or not and if I needed to be prepared for them to spawn.
<Oscar breeding can be quite a rewarding as well as demanding hobby.>
They constantly follow one another around the tank and share the feeder fish I have given to them. They seem to be the best of friends.
<These are not typically signs that instantly tell you it's a breeding pair, I have known fish that never bred to do similar actions.>
They are only about 2-3 inches at this point so I am wondering if these two have paired with one another?
<That is far to small to tell if they are paired or not, When they get around 6-8 inches you will be able to tell if they are paired. If not be careful some Oscars if not given enough room can become aggressive to one another. If they continue to spend time with each other as they mature, then chances are good that you do have a male/female pair of Oscars.>
Thanks for all of the help Eli, Pittsburgh, PA
<There are loads of resources online to help with caring for Oscars, please look at our cichlid section on WetWebMedia.Com. Good Luck.-Magnus.>

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