Oscar growth tips

Supalah17

Candiru
MFK Member
Feb 21, 2014
257
73
46
Buffalo, New York
Tank #6 in my fish room is on order right now, but the stocking is set, it’s a 120g (4’x2’x2’) and I have an FX6 with some pre cycled media in it waiting. I’m putting a single Oscar in there in honor of my late family member who bred them for decades.

There are so many varying statements out there on Oscars and their maximum size, but consistently I see “18 inch max size in the wild, 12-13 inch max in captivity”. My question is simply, are all tank bred Oscars just naturally going to be smaller, or does this come from generally poor husbandry and barely-big-enough tanks?

Given that the Oscar is going to have a whole 120 gallons to himself (seems double what most people put them in), will it be possible to truly get his wild size out of him?
 

TwoHedWlf

Redtail Catfish
MFK Member
Mar 2, 2017
1,376
1,577
154
42
New Zealand
Tank #6 in my fish room is on order right now, but the stocking is set, it’s a 120g (4’x2’x2’) and I have an FX6 with some pre cycled media in it waiting. I’m putting a single Oscar in there in honor of my late family member who bred them for decades.

There are so many varying statements out there on Oscars and their maximum size, but consistently I see “18 inch max size in the wild, 12-13 inch max in captivity”. My question is simply, are all tank bred Oscars just naturally going to be smaller, or does this come from generally poor husbandry and barely-big-enough tanks?

Given that the Oscar is going to have a whole 120 gallons to himself (seems double what most people put them in), will it be possible to truly get his wild size out of him?
Definitely biggest factor imo is poor husbandry. Not enough food, not enough water changes, not enough room, bad water quality... All pretty closely related though.
 

Supalah17

Candiru
MFK Member
Feb 21, 2014
257
73
46
Buffalo, New York
Definitely biggest factor imo is poor husbandry. Not enough food, not enough water changes, not enough room, bad water quality... All pretty closely related though.
Good to know, thanks! I’m medically retired so maintenance won’t be an issue, hopefully the tank size, the filter size, and good feeding will work for me. I breed black worms, ghost and cherry shrimps and guppies for the occasional treat for some of my other fish. That and a never ending supply of various Hikari cichlid pellets, frozen veggies, frozen foods, etc.
 
  • Like
Reactions: Tony A.

Drstrangelove

Potamotrygon
MFK Member
Oct 21, 2012
2,694
1,220
164
San Francisco
There are so many varying statements out there on Oscars and their maximum size, but consistently I see “18 inch max size in the wild, 12-13 inch max in captivity”. My question is simply, are all tank bred Oscars just naturally going to be smaller, or does this come from generally poor husbandry and barely-big-enough tanks?
I've seen people claim an 18" Oscar, but I've never seen it proved. I think 15-16" is the correct number, but who knows other than God what is the maximum size.

An 18" Oscar would weigh nearly 4 pounds and dwarf the world record per the IGFA.
http://wrec.igfa.org/WRecDetail.aspx?uid=5456&cn=Oscar#.WyXHMaczouU


As far as what is genetic (bred) versus environment (husbandry), I'd suspect that most captive Oscars are capable of 14-15", but fail to get close due to poor conditions in the tank. Obviously, there is a non-zero probability that tank-bred and farm-bred Oscars will only reach a smaller size due to breeding methods. I can't say if anyone has done the genome and can verify that, but human interaction has normally altered animals.
 

TwoHedWlf

Redtail Catfish
MFK Member
Mar 2, 2017
1,376
1,577
154
42
New Zealand
Yeah, for the length you also have to keep in mind that most people will measure the overall length while trying to brag about their fish's size. But the proper way for most purposes is the standard length, from nose to the base or fork of the tail.

My redspot in the tank next to my computer is conveniently up against the glass for me to measure his tail. That's a good 4" difference in length in his case.
 
  • Like
Reactions: Drstrangelove

Jexnell

Redtail Catfish
MFK Member
Jul 17, 2017
4,057
7,296
154
PNW
Seems your golden, plenty of water changes, I do 50%every other day, good food.
The only thing I would argue is a 6ft tank. I saw a dramatic improvemnt in my O when I moved her to a 6ft. It was from a 55gal, but still them 2ft made a big difference in her.
 

fishbum

Piranha
MFK Member
Nov 10, 2007
1,930
63
81
Antarctica
That tank is perfect for an Oscar. They don't grow to 18". Now a day if they did grow that size, there would be pics. It's a bit irritating this myth is still going around. It's seems to be perpetuated by people on forums who read or heard that somewhere, and keep repeating it. Most of these folks have never owned one themselves but hey will argue it till they are blue in the face. Lesser forums like "fishlore" seem to be the leader in this false information.

Regardless, its sounds like you have this figured out. Good food and clean water is all they need. Provide that, and you should have a nice 12" Oscar before you know it.
 
  • Like
Reactions: Supalah17

Supalah17

Candiru
MFK Member
Feb 21, 2014
257
73
46
Buffalo, New York
That tank is perfect for an Oscar. They don't grow to 18". Now a day if they did grow that size, there would be pics. It's a bit irritating this myth is still going around. It's seems to be perpetuated by people on forums who read or heard that somewhere, and keep repeating it. Most of these folks have never owned one themselves but hey will argue it till they are blue in the face. Lesser forums like "fishlore" seem to be the leader in this false information.

Regardless, its sounds like you have this figured out. Good food and clean water is all they need. Provide that, and you should have a nice 12" Oscar before you know it.
My Uncle Jimmy who bred them had a few massive Oscars back when I was a kid, so that definitely affected my ideas on Oscar size. Just have to keep remembering that those were show bred award winners for size and body shape, not a standard Oscar I could buy at a fish store.
 
  • Like
Reactions: fishbum

Tony A.

Dovii
MFK Member
Aug 22, 2016
863
794
105
64
Tank size,water,and good food, .Lots of good pellits. And the veggies. Most people will feed them feeders. Oscars are not fish eaters. But it sounds like your on the right track.
Good luck.
 
zoomed.com
hikariusa.com
aqaimports.com
Store