CichlidFish.com - Fish That Think.

hello im new to the site and need information on why my oscars are fighting

i have two oscars, a red and a tiger i bought the red first he was a tiny little thing when i bought him.    probably 2 months later i purchased the tiger quite a bit smaller then the red thus the names Big oscar (red) & Little oscar (tiger) its probably been about 8 months or so and now little oscar is bigger then big oscar. there roughly about 8-9 inches long and ive noticed that big oscar is starting to have what looks like fish bruises around his mouth.      curious as to whats going on ive been paying more attention to them quitly watching for like hours @ a time

what there doing is opening there mouths real wide a spreading there gills out and then charging into the others mouth very violenty and thrashing about. now usually they do a little chase game but never something like this

i have a 75 gallon tank i do 50% water changes about once a week or so the water is emaculate and the only other fish i have is a pleco i figured since little oscar is bigger then big oscar now they were fighting for dominance not sure though. should i put a divider in the tank ? i feed them chiclid pellets and everyother day they each get a feeder

what should i do if anything???????????   

Keep an eye on them.  Is there any aspect of play that seems to be involved, or is it fighting?  Not always easy to tell.  It could be that they're both males, and fighting for dominance of the tank.  If it keeps up, you may have to put in a divider, or put one of them in a different tank.  They're at the "terrible teens" stage now, and very conscious of territory and raging hormones.  Could also be mating behavior.  You'll have to use your judgement -- you're there looking at the fish, and I'm not.  Keep us posted!

well not sure if its play or what cause its very different then their usual play much more violent then before but i will keep an eye on them simply cause i love them both and would hate to lose either one possible mating i guess but i have no clue of there sex is there any obvious way to tell if they are male or female?  i'll wath the tank a while tonight and repost tomorrow thank you for the info =)

If you have one that usually starts the fight you could remove it for a little while, then when you put it back in, the territory will now belong to the more timid one which might solve the problem.

If it's mating behavior you should also see them doing alot of head twitching, and if you have a nice flat rock they will start cleaning it for a place to lay eggs.  When my mating pair were in a smaller tank they use to try to push on the glass with their mouths trying to make the tank bigger.  I'm glad they didn't take a swimming start at though cause they pushed so hard they would have hurt themselves easy..