I have written two posts about his tail jerking really bad and I have had great responses to what people think it may be. He is not acting himself. He looks lost. He is trying to eat and grab the crikets, krill and pellets but can't. He is bumping into everything in the tank. I had him since he was 2" and now is 11". I have had him for about 3 years. I am so concerned about him.

It's a 75 gallon tank with 2 11" in Oscars and a 13" placostomus

Water temperature is 76

Checked all water levels and they are all very good.

He doesn't come to me like he used to and when he sees a shadow come near tank he freaks out.

I went ahead and bought an "ALL-IN-ONE Treatment" just to see if that helps.
The first day of treatment will be today (for 5 straight days).

Any suggestions?

Thanks!

i had check the previous video and i can not find problem in it...
except the normal falling down.... and yes, the other one put the
head against the driftwood...and doesn't mind the falling dried
shrimp. but one can only think they are full.

btw, 2 x 11 oscar in a 75 gal with 13 inches plecs produces a lot
of waste. perfect water is not perfect at all unless we knew the
data...exact param,eter : ammonia? nitrite? nitrate? pH? the presence
of those decors and driftwood reduces the water volume, thus you have
less than 75 gal. your tank is getting smaller for them.

increase the temp to 80, put additional aeration of air bubbles while
medication is on going. i am not use to that kind of meds but temp
help to eliminate other source of illnesses.

Thanks so much. Hey, could it be possible that my oscar swallowed a rock and can't pass it? He has not pooped since yesterday early morning so that's about 2 days. I am concerned that is the problem. He was always scooping a large amount of rocks and relocating them.

scooping, bulldozing, and moving substrate is normal to full grown oscar..
i wouldn't worry about it.... i suggest you put a clean regular slate in the
substrate.... and if they tend to clean it up, and test the stability, then
they might be on the spawning process.

but still, i suggest to get the exact water parameter to make it sure.
3 years oscar at 11 inches is just an average size. my o had reached
the 14 inches mark on thier 27 month old.

I wouldn't worry about eating stones or rocks, most of the time they slip out the gill on the side you can't see. As for eye sight, if it is damaged it could take up to 5 months to heal or it may not get any better at all.

any treatment you use won't help a sight problem. only quality water will help this if at all. I am not totally sure a treatment will help, your oscar is acting very clumsy like a sight problem. the tail shaking could be to a nervous reaction to this blindness or more likely a nerve system infection. keeping a close eye on it is probably your best option. I wouldn't worry to much you are doing all you can, and the fact you noticed a little change in its behavior shows you care for them.

as others have said need to know the water quality, COULD be a form of ammonia burning,
but could be lots of things, have you done a partial water change?
as that does more than most meds'
good luck

There isnt much you can do if your oscar loses its sight, the best thing you can do is to keep your water in tip-top condition and hope things get better

Thank you all for all your help and suggestions. I did go visit and called a fish expert. She knew immediately all the symptoms before I could finish. She suggested the following:

Melafix and Pimafix and to continue the water tablets I started. She knew about the vision problem, the tail jerking and his struggle with eating. She also said to give him some of his pellets along with the peas in order to keep some familiar foods for him. She also thought that since I had just given them live crickets that there was a great possibility that as the cricket struggled inside of him (since they swallow them live), that the cricket ripped some of his insides. She mentioned that if there were any rips in his inside scales, it would start affecting his tail first. She suggested the two meds for 7 straight days, then do a 25% change and if i don't see a significant change to do 7 more days and that should take care of the problem. She even knew the eye that he lost his vision from. She called it "eye cloud". I pray all this works. Thanks again yall!

I don't I crickets can survive the onslaught of an Oscar. Ive seen my O hit a cricket and spit it out and it seems quite dead. Also, Oscars like saltwater groupers have teeth in their throats that allow them to grind up their food.
Some people say they can even hear their Oscars grinding up pellets.

first time to hear that a cricket could harm an oscar just like that...
i could not imagine that little creature could still kicked inside an
oscar... oscar has a very strong throat muscle and the cricket should
had been squeezed to death before swallowing.... i doubted the allegation.

nevertheless...good luck...hope the lfs suggestion works for you....

I to would be very surprised if a cricket could harm the inside of a oscar. I have seen them eat mice and frogs live. anyway lets hope the meds work, and keep us posted how its doing please.

it is always advisable to cut/rip the hind legs of the cricket/grasshopper b4 feeding them to the fish/bird. its sort of a standard practice here in my place.