CichlidFish.com - Fish That Think.

I'm trying to see if I can find a cached copy of our old OSCARS page that I wrote when I first started this website. If anyone finds more pieces of it please let me know, I think it was lost in the hard drive crash. So far I found this snippet using google:

[b]More and more everyone is posting everywhere with godlike authority that it is impossible to sex oscars short of seeing them spawn. That is NOT true! One sure way is through venting, where you analyze size and characteristics of their vents. Although hard to tell unless raised up together in same environment, females will have a more round head, also be more compressed and shorter. Males will have larger/longer fins. Males will generally have a more pointed 2nd dorsal fin(top fin next to tail). Females will have more of a rounded dorsal fin. Males are also more brightly colored. This is best noticed with cricles that surround eyespots or other areas that don't change with mood. And yes, the male will usually be more aggressive than the female. Another hint as to gender is the presence of DARK SPOTS at the base of the dorsal fin. Some males have 3 dark spots at the bottom of the dorsal fin. You may see that some of the dark spots may become "eye" spots like the one on the tail, encircled by red color. If your Oscar has 2 or 3 dark spots you should start looking for an Oscar who's laid eggs. Beware, that many male oscars do NOT have these 3 dark spots at base of dorsal fin. Males will generally have more red dots on fins, some say around gill area also. Soon I will add the SECRET method used by breeders to sex oscars at a very young age.[/b]

check the mods and admins board

There is one BIG BIG BIG BIG BIG BIG BIG sexing aid you forgot. Egg tubes. Going by your description of males I would assume I had all male oscars, but when my tiger oscars put down egg tubes I quickly realised that two were girls. And no they haven't bred *sigh*.
The spots you were talking about on the anal fin i think are called egg spots. More common with african cichlids such as Hongi and zebras.

And there's my two cents

Yea, you're right, that was just a small excerpt, I talked about the ovipositor on the old pages and in fact I even had a picture showing the ovipositor of female oscar etc... but my point was that you could do a 'decent' job with sexing oscars just by observing them from a distance. There's another trick I've noticed in terms of looking at their genital papillae which is easy to spot without close examination, ie if the genital papillae is straighter facing down or at an angle and this can be noticed easier then doing the entire venting exercise picking up the fish etc and comparing, and I considered venting, well, cheating
I had fun trying to figure it out just by observing mine without peeking too closely at the genital papillae, that's kinda rude anyway

The key to the dorsal and anal fin 'egg' spots I think is not as much the amount of red surrounding the black as what happens to the spots when they get excited, mating behavior or fighting etc....also, some males do not have a pointed dorsal fin at all, but have it very rounded though usually when that's the case you notice an enlargement at the end, an upward slope and then a nice round lobe of good size. I also think there is a difference in head shape between male and female, call me crazy but there was a point I swore the females looked 'cuter' than the males
But seriously don't laugh too hard, I really do believe there's some quantifiable difference in head morphology, I had written down my obervations (damn that hard drive crash) but if I recall correctly, the females had not just a smaller/narrower head but the angle of the mouth was a bit different or relation/distances of head characteristics......

DISCLAIMER: Hey if you spent HOURS and HOURS continuously watching a bunch of oscars in a tank day after day you might go Crazy Too!!

With my four oscars, I have two reds and two tigers, the tigers are female and the reds are male. They always pair up differently with eachother, which was confusing to say the least, cause I could tell them apart from markings and fighting scars, but when they did pair off they never had favorites. There is no difference in colour brightness, fin lengths, head shapes etc. The only thing I got was seeing egg tubes from the tigers. The reds have never produced them and the tigers are always dominant. Strange but I believe it's due to their size difference and being bossy to get to food.

For anyone who wishes to breed oscars, your safest bet is with 10 or more juvenilles to start with. the tank needs heavy filtration, two internal filters on the sides and an external cannister. These fish will grow and they will get dirty. The reason for so many oscars is that because they are such aggressive fish, I've found that without fail, increasing the amount of fish in the tank REDUCES fighting, because the fish get so exhausted of being territorial. Every time they swim around there's a fish to fight. Pretty shortly they don't bother. Just make sure you have as close a size as possible and feed evenly to prevent domination.

Plenty of teracotta pots placed in the tank along with limestone will be perfect for territorial seclusion and pH buffering in the water. A higher pH mean that from nitrogenous waste, more stays in the less toxic ammonium(un-ionised) while less is ionised into ammonia. The reason is due to the lower amount hydrogen in concentration in the water. Really important because this is a high food demand fish with a high output rear and...and gills lol.

Oh and for anyone trying to reduce nitrogenous waste in their tank, here's a tip.....
The higher the protein content of the food the lower the waste output. Try to feed your fish food that is going to give them their staple requirements. the more you need to feed them because of the lack of quality, the higher risk their waste is.
40% is a fantastic protein content for food.

Well, I can tell you that after making all my observations I was able to go out to fish store and buy one "female" oscar just by observing through tank in store, and yes maybe I got lucky, I just didn't think so, I'd be rusty now but I stand by my assertion that's its possible to distinguish sex by observation with decent (not 100% of course) accuracy (my main experience was with Tiger oscars...).
Good point about the food, the more often you need to feed the more chance of leaving food in tank rotting, should be cleaned/removed along with the waste....

At work today I sat down and stared at some juvenile tigers for a while, probably too young to be prominent but there were few that I could see which had more pointed and longer fins than the others, also a bit more boisterous...perhaps I spotted myself some males?